Taphonomy of Yellow-legged Gull (Larus …...10 E-mail: [email protected];...
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Taphonomy of Yellow-legged Gull (Larus michahellis Naumann, 1840) pellets from the Chafarinas Islands
(Spain)
Journal: Canadian Journal of Zoology
Manuscript ID cjz-2018-0139.R1
Manuscript Type: Article
Date Submitted by the Author: 16-Jul-2018
Complete List of Authors: Guillaud, Emilie; Museum National d'Histoire Naturelle, Morales-Muñiz, Arturo ; Universidad Autonoma de Madrid Facultad de Ciencias Economicas y Empresariales, Dept. BiologiaRosello Izquierdo, Eufrasia; Universidad Autonoma de Madrid Facultad de Ciencias Economicas y Empresariales, Dept. Biologia Calle Darwin 2Béarez, Philippe; Museum National d'Histoire Naturelle, UMR 7209 55 rue Buffon
Is your manuscript invited for consideration in a Special
Issue?:Not applicable (regular submission)
Keyword: Yellow-legged gull, Larus michahellis, Pellet, Fish bone, Taphonomy, Chafarinas Islands
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1 Taphonomy of Yellow-legged Gull (Larus michahellis Naumann, 1840) pellets from the
2 Chafarinas Islands (Spain)
3 Emilie GUILLAUDa,c, Arturo MORALES-MUÑIZb, Eufrasia ROSELLÓ-IZQUIERDOb,
4 Philippe BÉAREZa
5
6 a Unité Archéozoologie, archéobotanique: sociétés, pratiques et environnements (AASPE),
7 Muséum national d’histoire naturelle, CNRS. CP 56, 57 rue Cuvier, 75005 Paris, France .
8 E-mail : [email protected]; [email protected]
9 b Laboratorio de Arqueozoología, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
10 E-mail: [email protected]; [email protected]
11 c Unité Histoire naturelle de l’Homme préhistorique (HNHP), Muséum national d’histoire
12 naturelle, CNRS. 1 rue René Panhard, 75013 Paris, France.
13
14 Abstract
15 Fish are consumed by many predators in addition to humans. Identifying the agent responsible for
16 an archaeological fish bone accumulation is a crucial yet far from straightforward task in the
17 absence of diagnostic criteria. It is for this reason that exploring the features of fish bone
18 collections produced by animals constitutes a key issue of archaeozoological research. In this
19 paper one such study is presented for the Yellow-legged Gull (Larus michahellis Naumann,
20 1840). A total of 48 pellets were collected in a colony of the species on two islands of the
21 Chafarinas archipelago (Mediterranean Sea). The analyses demonstrate that fish remains,
22 represented by 13 species and one genus, made up 93% of the 2,789 identified remains. Most
23 assemblages were dominated by the European pilchard (Sardina pilchardus (Walbaum, 1792)).
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24 Our study indicates that digestive processes modify skeletal elements through abrasion and
25 fragmentation. Based on the modifications that were recorded, a set of diagnostic criteria is
26 proposed to serve as proxies for spotting fish bone deposits produced by gulls on archaeological
27 assemblages.
28
29 Résumé
30 En dehors des populations humaines, les poissons sont inclus dans l'alimentation d'un large
31 éventail de prédateurs. Pour cette raison, l'identification de l'agent responsable des accumulations
32 d'os de poisson, en contexte archéologique, est une tâche cruciale mais souvent loin d'être simple
33 en l'absence de critères diagnostiques. L'observation des informations diagnostiques produits par
34 des accumulateurs non humains, sur des ossements de poissons, constitue donc une question clé
35 de la recherche archéozoologique. Dans cet article, est présenté l’étude taphonomique de pelotes
36 provenant d’un rapace diurne opportuniste : le Goéland à pattes jaunes (Larus michahellis
37 Naumann, 1840). L'analyse de 48 pelotes collectées sur deux îles de l'archipel des Chafarinas
38 (mer Méditerranée), a montré que les restes de poissons -13 espèces et un genre- représentaient
39 93% des 2789 restes identifiés sur l’ensemble des assemblages. Le spectre est dominé par la
40 sardine (Sardina pilchardus (Walbaum, 1792)). Notre étude a démontré que les processus
41 digestifs modifient souvent les éléments du squelette par abrasion et fragmentation. En se basant
42 sur les modifications de surface, un ensemble de critères a pu être identifié concernant le goéland
43 à pattes jaunes. Ces critères peuvent servir de d’indicateurs pour repérer l’impact de cette espèce
44 sur les assemblages archéologiques.
45
46 Keywords
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47 Yellow-legged gull, Larus michahellis, pellet, fish bone, taphonomy, Chafarinas Islands.
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49 Introduction
50 In zooarchaeology, the identification of species is not restricted to anatomy and taxonomy.
51 Determining the origin of an archaeological deposit, for example, requires the accumulating
52 agent to be identified and that task, in turn, requires taphonomic criteria. For fishes, preyed by
53 many animals in addition to humans, an improvement in excavation and retrieval techniques has
54 generated a large number of sites where fish bones are found. Yet the origin of their deposits
55 remains unspecified more often than not due to a lack of taphonomic criteria. On caves, the
56 problem is compound by a spatio-temporal coexistence of fish predators such as carnivores,
57 raptors and humans, whose meal leftovers get mixed in the archaeological deposits. To
58 complicate matters further, the remains of those predators may not appear in the deposits so that
59 their presence can only be inferred through criteria such as the size range of the fish taxa present,
60 marks recorded on fish bones, etc. Under such circumstances, only a taphonomical analysis will
61 manage to correctly infer the accumulating agent (Andrews 1990; Fernández-Jalvo and Andrews
62 2016).
63
64 Actualistic studies are a fundamental tool for taphonomical analysis since the baselines they
65 provide allow zooarchaeologists to correctly interpret data from the past. In the case of birds,
66 dietary studies based on ocular inspection of pellets are often biased since remains tend to be
67 digested to the extent that even complete bones can be difficult to identify. Here lies the
68 importance of evaluating fish remains modifications under closer scrutiny. Comparative analyses
69 of diets, however, are rarely carried out from a taphonomical standpoint. To date, few studies
70 exist that allow one to set apart fish accumulations produced by humans (Jones 1986) from those
71 produced by predators (Russ and Jones 2011; Guillaud et al. 2017) or those of mixed origin (Russ
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72 2016; Morales in press). Previous taphonomical analyses of bird meal leftovers have focused on
73 the Eurasian eagle owl (e.g. Nicholson 1991; Le Gall 1999, Russ 2010; Russ and Jones 2011),
74 barn owl (Broughton et al. 2006), bald eagle (Erlandson et al. 2007) and common kingfisher
75 (Frontin 2017). Although gulls at large (i.e. Laridae) are regular fish-eaters on marine, lacustrine
76 and riverine habitats, the marks they leave on fish bones have not been investigated from a
77 taphonomical standpoint.
78
79 In this paper, we provide an overview of the range of species consumed by the Yellow-legged
80 gull (Larus michahellis Naumann, 1840) in the Strait of Gibraltar area and the traces it leaves on
81 fish bones. An opportunistic and eclectic predator, the Yellow-legged gull’s diet is still poorly
82 documented no study existing that addresses the issue of traces left on fish bones (Ramos et al.
83 2006; 2009). A vicariant species of the European herring gull (Larus argentatus Pontoppidan,
84 1763), we also targeted the Yellow-legged gull with the aim of developing a taphonomical
85 baseline for gull diet studies in the Northern Atlantic in general (Del Hoyo et al. 1996; Collinson
86 et al. 2008).
87
88 Study area
89 The Chafarinas Islands (Fig 1) are located in the southern Alborán Sea, off the eastern
90 Mediterranean coast of Morocco, facing the city of Melilla (35o 11’ N, 2o 26’ W). The main
91 islands of this volcanic archipelago are Congreso, Isabel II and Rey. Only Isabel II Island has
92 been permanently inhabited since 1848 by a Spanish garrison. In 1982, the islands were classified
93 as a National Hunting Refuge Area (Royal Decree 1115/82). Later, in 1989, they were declared a
94 Special Protection Area for Birds (SPA; Directiva 79/409/EEC) and in 2006 they became a Site
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95 of Community Importance (SCI) of the Natura 2000 network (EEC Habitats Directive 92/43)
96 (Guallart Furió and Afán Asensio 2013).
97
98 Figure 1: Location of sites mentioned in the text.
99
100 Several gull species are found on the Chafarinas, some confusion existing when distinguishing
101 the Yellow-legged Gull and the endangered Audouin's Gull (Ichthyaetus audouinii Payraudeau,
102 1826), whose largest nesting colony in the Mediterranean is found on Congreso island. The two
103 species feature similar life histories and their breeding colonies lie adjacent to each other despite
104 the Yellow-legged gull being a major predator of Audouin’s gull’s eggs and chicks (Oro et al.
105 1999).
106
107 Material and methods
108 A total of 56 regurgitation pellets were collected at Congreso and Rey islands in June 1965, June
109 1968, and April-June 1969. At Congreso, pellets were collected around Yellow-legged gull nests
110 lying close to the breeding colony of Scopoli's shearwater, Calonectris diomedea (Scopoli, 1769).
111 On Rey Island pellets were collected around the nests. The identification of pellets as belonging
112 to the Yellow-legged Gull was carried out in the field by Varela and De Juana (1986) (Fig 2).
113
114 Figure 2: Pellet of Yellow-legged Gull.
115
116 Each pellet was cleaned through a 0.5 mm mesh sieve with fresh tap water and 70% alcohol, and
117 then air-dried on filter paper. Each bone was identified through anatomic and taxonomic
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118 comparison using one of the authors’ (AMM) reference collection housed at the Laboratorio de
119 Arqueozoologia, Universidad Autonoma de Madrid (UAM). Remains were inspectioned both
120 macroscopically and microscopically. A binocular microscope was used for the identification of
121 small skeletal elements and for the observation of marks. For quantitative purposes, the number
122 of identified specimens (NISP) and the minimum number of individuals (MNI) were used (Reitz
123 and Wing 2008). MNIs were estimated based on the number of first vertebrae and paired bones,
124 taking into account side (left/right) and size (Poplin 1976). Specimen size was inferred through
125 direct comparison with modern reference specimens. Surface modification was recorded
126 following Nicholson’s method (1991), the percentage of visible surface present adapted from
127 Villa and Mahieu (1991). Bone digestion was recorded according to a five category scale,
128 namely: absent (0), minimal (1), moderate (2), heavy (3) and extreme (4-5) (Fernández-Jalvo and
129 Andrews 2016). Percentage of bone representation follows Dodson and Wexlar (1979) (PR =
130 FO/FT x MNI, where FO is the number of elements in the sample and FT the number of elements
131 in the prey’s skeleton excluding fin rays, pterygiophores, ribs and scales). This formula also
132 provided an overview of skeletal representation, as frequencies from each element were pooled
133 from all pellets.
134
135 Results
136 A total of 48 pellets from the islands of Congreso (N = 34) and Rey (N = 14), representing 2,789
137 identified remains, were analyzed for this study (Table I).
138
139 Table I. Number of identified remains in the Yellow-legged gull pellets. NISP: number of
140 identified specimens; (%): percentage of identified specimens
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142 Fish represented 93% (NISP = 2,602) of the total sample (Table I), most pellets containing the
143 bones of just one individual. Detailed counts for Congreso Island (NISP = 1,505) and Rey Island
144 (NISP = 1,097) are given in Tables II and III. Several pellets also contained remains of birds
145 (chicken), mammals (mice, rabbit, sheep), crustaceans (crabs), molluscs (cuttlefish), insects
146 (Tenebrionidae) and seeds for a total non-fish NISP of 170 (17 remains could not be identified
147 taxonomically).
148 Thirteen species and one genus of fish were identified. These include Eel, Anguilla anguilla
149 (Linnaeus, 1758); Bogue, Boops boops (Linnaeus, 1758); White sea bream, Diplodus sargus
150 (Linnaeus, 1758); European anchovy, Engraulis encrasicolus (Linnaeus, 1758); grouper,
151 Epinephelus sp.; Sand steenbras, Lithognathus mormyrus (Linnaeus, 1758); European hake,
152 Merluccius merluccius (Linnaeus, 1758); Axillary sea bream, Pagellus acarne (Risso, 1827);
153 Common pandora, Pagellus erythrinus (Linnaeus, 1758); Red porgy, Pagrus pagrus (Linnaeus,
154 1758); European pilchard, Sardina pilchardus (Walbaum, 1792); Round sardinella, Sardinella
155 aurita Valenciennes, 1847; Salema, Sarpa salpa (Linnaeus, 1758 ) and Atlantic horse mackerel,
156 Trachurus trachurus (Linnaeus, 1758).
157
158 In decreasing order of importance, the most frequently represented family was Clupeidae
159 (Sardine; NISP = 1476; MNI =50), followed by Sparidae (Sea breams; NISP = 218; MNI = 16),
160 Engraulidae (Anchovy; NISP = 100; MNI = 6), Anguillidae (Eel; NISP = 58; MNI = 4);
161 Carangidae (Horse mackerel; NISP = 35; MNI = 5); Merlucciidae (Hake; NISP = 15; MNI = 2)
162 and Serranidae (Groupers; NISP =1; MNI = 1). Estimated mass ranged from less than 10 g to
163 200g (10 to 30 cm TL) and up to 2000 g (40 cm TL) for the White sea bream.
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164
165 Table II. Number of identified and unidentified remains per Yellow-legged gull pellet. NISP:
166 number of identified specimens; (%): percentage of identified specimens.
167 Table III. Number of identified remains per species and per pellets of Yellow-legged gull pellet.
168
169 Anatomical representation
170 Only 42% of the remains have been identified both anatomically and taxonomically. Among
171 these, 7% (169) belonged to the cranial skeleton and 35% (915) to the axial skeleton.
172 Unidentified vertebrae fragments, including neural or haemal processes and scales, represented
173 58% (1518) of the remains.
174
175 Sardine was represented by the entire skeleton, with caudal vertebrae being the most frequent
176 category. Caudal vertebrae also dominated the anchovy, eel, hake and horse mackerel samples.
177 For sea breams, the dentary was the most frequently represented bone. The maxilla was the only
178 element present for grouper.
179
180 Bone modification
181 Bone surface damage was recorded with a stereoscope. Only 3% of the elements lack traces of
182 digestion. The frequencies of those that do include 9% altered to a light degree (1), 6%
183 moderately affected (2), 41% featuring heavy modification (3), and 22% extremely damaged (4-
184 5) (Table IV). Eel, sea bream and grouper exhibited no digestion traces or else minimal digestion.
185 Horse mackerel remains exhibited moderate digestion for the most part whereas sardine, anchovy
186 and hake bones were all heavily altered by digestion. Within a single pellet, the intensity of
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187 digestion can vary from bone to bone, as this may depend on the type of bone and on how long
188 ingestion lasted.
189
190 Table IV. Percentage and classes of digestion for fish taxon by number of remains (NISP) and
191 percentage
192
193 Deformation of skeletal elements was infrequent. The rounding and polishing of articulation
194 edges observed under the scanning electron microscope (SEM) allowed us to recognize advanced
195 degradation along with digestion pits (Fig 3). Several types of alteration were visible, including
196 fissures (NISP = 37), exfoliation (NISP = 34), and abrasion/polishing marks (NISP = 1,141).
197 Otoliths and eye lenses were well preserved and showed no evidence of alteration.
198
199 Figure 3: Modification of a precaudal vertebra of Anguilla anguilla (scanning electron
200 microscope).
201
202 Survival rate, fragmentation and loss of skeletal elements
203 Yellow-legged gull pellets were characterized by the presence of complete and fragmented
204 elements within the same pellet. The elements that were retrieved exhibited a moderate degree of
205 integrity. The frequency of broken elements reached to 40% of the remains. Three fish specimens
206 were almost intact but were missing the head (Fig 4).
207
208 Figure 4: Degrees of digestion.
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209 a) Undigested Boops boops, b) Sardine bones (loss absent); c) Precaudal vertebra of sardine
210 (minimal digestion); d) Caudal vertebra of sardine (moderate digestion); e) Sardine vertebra
211 exhibiting intensive digestion; f) and g) From the same pellet, two patterns of digestion of
212 precaudal vertebra of eel (lack of and heavy digestion); h) and i) From the same pellet, two
213 patterns of digestion of opercula of sardine (lack of and moderate digestion).
214
215 Only 29 skeletal elements from approximately 200 bones composing the entire skeleton were
216 recovered after the digestive process (Fig 5, Table V). The percentage of representation as per
217 Dodson and Wexlar (1979) evidenced good preservation for caudal vertebrae (PR = 98.5% for
218 Anchovy, 62.4% for Sardine; 40.9% for Hake and 28% for Eel). The basioccipital was best
219 preserved in Sea breams (PR = 37.5%), and so were the maxilla and the quadrate in the Horse
220 mackerel (PR = 12.5%). For Grouper, only one maxilla was recovered. Within the Sea breams,
221 the dentary was well preserved in White sea bream (PR = 50%) and Common pandora
222 (PR = 100%), whereas the maxilla was well preserved in Sand steenbras and the premaxilla in the
223 Axillary sea bream (PR = 75%). In Red porgy, the dentary and maxilla were present with
224 identical proportions (PR = 50%) whereas for Salema the samples included articular, cleithrum,
225 coracoid, parasphenoid, scapula, subopercle and supracleithrum (PR = 100%). The bones least
226 represented include the precaudal vertebrae of Bogue (PR = 5%) and Salema (18%), the caudal
227 vertebrae of the Axillary sea bream (PR = 2%), and the premaxilla (Red porgy) and articular plus
228 dentary for Sand Steenbras (PR = 25% in all cases). Bones were best preserved in specimens
229 weighing either around 200-300 g (Hake and Sea breams) or 20-60 g (Eel, Horse mackerel,
230 Sardine and Anchovy).
231
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232 Figure 5. Skeletal elements before and after digestion in Yellow-legged gull pellets (Common
233 carp skeleton, modified from Tercerie et al. 2016 (osteobase.mnhn.fr) and Archaeological Fish
234 Resource (http://fishbone.nottingham.ac.uk/). For abbreviations see Table V.
235
236 Discussion
237 Generalist and opportunistic habits have been reported on other Yellow-legged gull colonies from
238 the Western Mediterranean. Examples include Bosch et al. (1994), who analyzed 85 pellets from
239 the Medes Islands and the Ebro Delta on the northeastern coast of Spain; Vidal et al. (1998), who
240 studied 350 chick regurgitates on colonies from those two localities plus others on the
241 Columbretes and Mazarrón islands; and Duhem et al. (2003a, b), who analyzed 1,192 pellets
242 from 6 colonies in southeast France (Ratonneau, Pomègues, Plane, Riou, Porquerolles, and
243 Bagaud). Consistent with the results of our analysis, these studies evidenced that fish were the
244 main prey of the Yellow-legged gull’s diet, and Anchovy and Sardine its favored species (Fasola
245 et al. 1989; Gonzáles-Solís et al. 1997). Fish nevertheless constituted a significantly smaller
246 percentage of food remains (65-85%) in those studies than appears to be our case. This might be
247 due to a combination of factors, the absence of substantial (human) dumpyards on the Chafarinas
248 being probably a crucial item. Failure to carry out taphonomic analyses on those samples does
249 not allow one to decide whether the fish retrieved derived from active fishing or from
250 scavenging. Studies from other regions do not exhibit such consistency in the dietary spectra.
251 López et al. (2016) studied 529 pellets and 465 fecal samples from the island of El Hierro in the
252 Canary Islands and found that fish represented only slightly over 30% of the identified remains.
253 Pellets consisted of 5% of marine invertebrates (including Crustacea) which frequencies rose to
254 19% in the fecal samples. Terrestrial invertebrates, including Pulmonata, Araneae, Isopoda,
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255 Julida, Orthoptera and Coleoptera, represented 60% of preyed items in pellets and 84% on fecal
256 samples. Terrestrial vertebrates (reptiles, mammals and birds) represented less than 5% of all
257 prey. These spectra hint at the presence of substantial vegetation on El Hierro island, and this
258 contrasts with the essentially barren landscape characterizing the Chafarinas archipelago. Also,
259 given that terrestrial invertebrates tend to be more frequent in gull pellets when scavenging is the
260 preferred feeding strategy, the data from El Hierro island stress the scavenging (i.e. generalist and
261 opportunistic) component in the feeding behavior of this species (Bernhardt et al. 2010; Matias
262 and Catry 2010).
263
264 The presence of a broad size range for eel and sardine indicates no selectivity of prey size. Fish
265 body size can also be interpreted in terms of season of capture. Seasonality may not only hold the
266 key to the shifting abundances of fish in pellets and fecal samples of the Yellow-legged gull, but
267 may also explain the dominance of sardine and snchovy that our study and the aforementioned
268 western Mediterranean ones reveal. The study by López et al. (2016) concluded that prey
269 abundances were linked not only to environment but also season. Apparently, when colonies are
270 located next to a continental platform, the proportion of marine prey is higher during autumn-
271 winter and decreases at other times of the year (Moreno et al. 2010). These differences in prey
272 composition can be explained by the availability of specific food resources for each colony.
273 When marine resources, in particular fish, diminish, gulls will tend to focus on alternative, easier
274 to obtain, foodstuffs (Bertellotti et al. 2001). The absence of a continental platform around the
275 volcanic Chafarinas Islands may help explain why, even during spring, fish made up such a high
276 proportion of the diet. But the time of the year when pellets were collected is also important.
277 June-July, for example, are the months when sardines and anchovies reach surface waters in the
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278 Alborán Sea during their spawning migrations. Under such circumstances, the abundance of these
279 Clupeiformes within the pellet samples makes a lot of sense.
280 In terms of dietary spectrum then, the results from our analysis appear essentially consistent with
281 the data that have been thus far published for this species. The food spectra of the Yellow-legged
282 gull in the Chafarinas islands reflect a combination of active fishing and scavenging of human
283 refuse deposits. Although no people are presently stationed on Congreso or Rey Islands, where
284 the breeding colonies of the species are located, the remains of birds and mammals, as well as
285 those of fish such as the White sea bream, appear to derive from a regular scavenging of garbage
286 dump yards of the garrison stationed at the island of Isabel II. On the other hand, most of the
287 fishes that made up the bulk of the spectra, in particular sardine and anchovy, appear to represent
288 active fishing on the part of gulls.
289
290 The general pattern of modification recorded in our samples was characterized by extensive
291 damage and evidence of bone digestion. The analyses indicated variations in terms of bone
292 modification, depending on the species but also even within the same species.
293
294 It is interesting to compare the Yellow-legged gull data with that from other fish predators.
295 Among the nocturnal raptors, the Eurasian eagle owl, Bubo bubo (Linnaeus, 1758), long
296 recognized as a recurrent accumulator of fish in archaeological deposits, has been the species
297 most intensively studied. Among the works of zooarchaeological relevance, in addition to Le Gall
298 (1999) who analyzed pellets from southeastern France and Guillaud et al. (in prep.) who analyzed
299 pellets from Tautavel (France), one needs to consider the trace analysis of a controlled feeding
300 experiment carried out by Russ (2010). The skeletal spectra from the latter analysis evidenced
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301 that almost complete fish skeletons were retrieved. Digestion traces were minimal and bone
302 deformations rare. Digestion damage included fissures, exfoliation, perforation, twisted bones
303 and beak impact marks. In the case of the Barn owl, Tyto alba (Scopoli, 1769), a study of 14
304 pellets from Homestead Cave (Utah, USA) also evidenced a high level of conservation and low
305 damage including feeble digestion traces (Broughton et al. 2006). Such facts notwithstanding,
306 rounding, pitting and deformation were recorded on a few bones.
307 Fewer studies of fish bone remains from pellets exist in the case of diurnal raptors. The common
308 kingfisher, Alcedo atthis (Linnaeus, 1758), was studied by Frontin (2017), yet her taphonomic
309 study covered only 10% of the available sample (NISP = 5868) and focused on vertebrae (no
310 cranial remains were analyzed). Frontin (2017) did not find any visible traces of manipulative
311 marks on her samples. Engström and Johnsson (2003; L. Johnsson pers. comm.) studied pellets
312 from the Great cormorant, Phalacrocorax carbo (Linnaeus, 1758) whose fish bones featured
313 intensive digestion marks, similar to those reported by Andrews (1990), and the most superficial
314 of the cranial bones were completely dissolved. Otoliths in cormorant pellets survived longer
315 than either bone or eye lenses.
316 As far as gulls are concerned, the most important study is that of Nicholson (1991), who collected
317 pellets from the European herring gull (Larus argentatus Pontoppidan, 1763) and the Greater
318 black-backed gull (Larus marinus Linnaeus, 1758) on Eileans and Skate Point in the Great
319 Cumbrae Islands (Scotland). In this case, out of a total of 84 pellets, only six contained fish
320 bones. The majority of pellets contained mollusk shells, crabs, beetles, algae and human
321 consumption waste. Fish bones exhibited a wide range of damage, including fragmentation and
322 digestive erosion. Cranial bones showed little damage whereas some vertebrae featured rounded
323 and lightly polished margins, a result of erosion by acids. Rarely were fish remains from one
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324 pellet homogeneously corroded, some being polished/rounded others not. Not surprisingly, given
325 the taxonomical proximity of these species to the Yellow-legged gull, the results from
326 Nicholson’s study appear fully consistent with ours.
327 Few fish bone studies have been carried out on carnivores, the spraints of the Eurasian otter,
328 Lutra lutra (Linnaeus, 1758), being the most appropriate analogue. The studies that have been
329 carried out report intensive modifications including chewed and crushed bones, along with
330 dissolution, pitting and rounding marks (Nicholson 2001, Guillaud et al. 2017). Fish bones
331 consumed by otters tend to be broken and digested to a degree that corresponds mostly with
332 category no. 5 (Andrews, 1990).
333
334 Several studies report that the variability of taphonomic marks, even within the same species,
335 may depend on factors such as age, size of the predator, size of the prey, prey availability and the
336 histological structure of the bones (Denys et al. 1995; Fernández-Jalvo et al. 2002). The time it
337 takes for a pellet to be produced depends on the type of prey ingested by the gull. Brown and
338 Ewins (1996) estimated that pellets can take several days to form but an experimental study on
339 the Great skua (Stercorarius skua Brunnich, 1764) evidenced that pellets took only 6-24 hours to
340 form after feeding (Votier et al. 2001). It appears that pellets are produced faster when they
341 contain an excess of non-digestible material. All these contingencies may help explain why in our
342 samples bones from the same species exhibited different intensities of digestion even within the
343 same pellet (e.g., some may have been immediately regurgitated, others later) and why some fish
344 were still almost intact. These studies also highlight variations in bone modification among the
345 different types of predators. Bone fragmentation and skeleton completeness in pellet assemblages
346 may also depend on the feeding habits of a bird (e.g., fisher or scavenger). These differences in
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347 feeding behaviour may also imply that preyed fish MNIs calculated for the total assemblage can
348 be far lower than the actual number of consumed fish.
349
350 The importance of recognizing non-human predators in archaeological assemblages is crucial for
351 the correct interpretation of any bone accumulation. Archaeological sites were often shared by
352 human groups, raptors and carnivores, thus their recognition enables researchers to access various
353 kinds of information. Spatial distribution can also potentially inform the analyst about the
354 specific fish accumulator at a given deposit. Nocturnal raptors bone accumulations tend to
355 concentrate next to their nests whereas diurnal raptors, including gulls, tend to concentrate their
356 food remains around or below roosting sites. This is also the case of otters which use spraints to
357 mark their territory, being thus prone to place meal leftovers on top of rocks and prominences
358 around their dens.
359
360 Conclusions
361 The available taphonomic studies of fish accumulations made by predatory birds and otters
362 provide evidence that traces of digestion vary among species. These studies also suggest that
363 archaeological fish deposits can be characterized by a combination of features, including the
364 variety of skeletal elements present, as well as by differing amounts of fragmentation and quite
365 specific bone surface alterations.
366 In this paper, we provide the first taphonomic study of pellets from the Yellow-legged gull. This
367 opportunistic species consumes a variety of live prey, including those around human refuse
368 grounds, as well as a variety of meal leftovers. Based on selected digestion traits on the skeletal
369 elements, heavy digestion and polishing rather than fragmentation appear to constitute the most
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370 relevant features of fish accumulations produced by this gull. Some pitting and rounded bones
371 may also be diagnostic. These results are consistent with those carried out previously on other
372 gull species.
373 To set up reliable baselines taphonomic analyses must be implemented for as many species of
374 fish accumulators as possible to develop a robust comparative frame for the potential recognition
375 of the specific accumulator agent, or agents, that operated at any given site.
376
377 Acknowledgements
378 This study was funded by a fellowship granted by the LabEx BCDiv of the Muséum National
379 d’Histoire Naturelle (Paris) and by the project “Ictioarqueologia de la prehistoria cantábrica:
380 Modelos para la caracterización de las primeras pesquerías europeas” (HAR 2014-55722-P) from
381 the Spanish Ministerio de Economía y Competitividad. We would like to particularly thank
382 Yolanda Fernández-Jalvo and Leif Jonsson for their advice, Arlene Fradkin for copy-editing, and
383 Christine Lefèvre, François Poplin and Jean-Bernard Huchet for their help with the identification
384 of birds and insects. Michel Lemoine is acknowledged for making the SEM pictures with the
385 neoscope of the “plateau archéobotanique de l’UMR 7209 équipement programme CoBota-IdF”
386 and Marie-Hélène Moncel for post-doctoral co-supervision.
387
388 References
389
390 Andrews, P. 1990. Owls, Caves and Fossils. University of Chicago Press (Chicago).
391
Page 18 of 39
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392 Archaeological Fish Resource [en ligne]. Available from http://fishbone.nottingham.ac.uk/
393 [consulté le 16 avril 2018].
394
395 Arizaga, J., Jover, L., Aldalur, A., Cuadrado, J.F., Herrero, A., and Sanpera, C. 2013. Trophic
396 ecology of a resident Yellow-legged Gull (Larus michahellis) population in the Bay of Biscay.
397 Mar. Environ. Res. 87–88 : 19–25. Available from
398 http://dx.doi.org/10.1016/j.marenvres.2013.02.016
399
400 Bernhardt, G.E., Kutschbach-Brohl, L., Washburn, B.E., Chipman, R.B., and Francoeur, L.C.
401 2010. Temporal variation in terrestrial invertebrate consumption by Laughing Gulls in New
402 York. Am. Midl. Nat. 163 : 442–454. Available from http://www.jstor.org/stable/40730938
403
404 Bertellotti, M., Yorio, P., Blanco, G., and Giaccardi, M. 2001. Use of tips by nesting Kelp Gulls
405 at a growing colony in Patagonia. J. Field Ornithol. 72 : 338–348.
406
407 Bosch, M., Oro, D., and Ruiz, X. 1994. Dependence of yellow-legged gulls (Larus cachinnans)
408 on food from human activity in two Western Mediterranean colonies. Avocetta, 18 : 135–139.
409
410 Broughton, J.M., Cannon, V.I., Bogiatto, R., Arnold, S., and Dalton, K. 2006. The taphonomy of
411 owl-deposited fish remains and the origin of the Homestead Cave ichthyofauna. Journal of
412 Taphonomy, 4(2) : 69-95.
413
Page 19 of 39
https://mc06.manuscriptcentral.com/cjz-pubs
Canadian Journal of Zoology
Draft
20
414 Brown, K.,. and Ewins, P.J. 1996. Technique-dependent biases in determination of diet
415 composition: an example with Ring-billed gulls. The Condor, 98 : 34-41. Available from
416 http://www.jstor.org/stable/1369505
417
418 Collinson, J.M., Parkin, D.T., Knox, A.G., Sangster, G., and Svensson, L. 2008. Species
419 boundaries in the Herring and Lesser Black-backed Gull complex. British Birds, 101(7) : 340–
420 363.
421
422 Del Hoyo, J., Elliot, A., and Sargatal, J.1996. Handbook of the Birds of the World. Vol. 3:
423 Hoatzin to Auks. Lynx Editions. (Barcelona).
424
425 Denys, C., Fernández-Jalvo, Y., and Dauphin, Y. 1995. Experimental taphonomy: preliminary
426 results of the digestion of micromammal bones in the laboratory. C.R. Acad. Sci., Ser. IIa: Sci.
427 Terre Planetes. 321(9) : 803-809.
428
429 Dodson, P., and Wexlar, D. 1979. Taphonomic investigation of owl pellets. Paleobiology, 5 :
430 275-284. Available from http://www.jstor.org/stable/2400260
431
432 Duhem, C., Vidal, E., Roche, P., and Legrand, J. 2003a. Island breeding and continental feeding:
433 how are diet patterns in adult yellow-legged gulls influenced by landfill accessibility and
434 breeding stages? Ecoscience, 10 : 502–508. Available from
435 https://doi.org/10.1080/11956860.2003.11682798
436
Page 20 of 39
https://mc06.manuscriptcentral.com/cjz-pubs
Canadian Journal of Zoology
Draft
21
437 Duhem, C., Vidal, E., Legrand, J., and Tatoni, T. 2003b. Opportunistic feeding responses of the
438 Yellow-legged Gull Larus michahellis to accessibility of refuse dumps. Bird Study, 50(1) : 61-
439 67. doi: 10.1080/00063650309461291
440
441 Engström, H., and Johnsson, L. 2003. Great cormorant Phalacrocorax carbo sinensis diet in
442 relation to fish community structure in a freshwater lake. Vogelwelt, 124(Suppl.) : 187–196.
443
444 Erlandson, J.M., and Moss, M.L. 2001. Shellfish feeders, carrion eaters and the archaeology of
445 aquatic adaptations. American Antiquity, 66(3) : 413-432. Available from
446 http://www.jstor.org/stable/2694242
447
448 Erlandson, J.M., Rick, T.C., Collins, P.W., and Guthrie, D.A. 2007. Archaeological implications
449 of a bald eagle nesting site at Ferrelo Point, San Miguel Island, California. J. Archaeol. Sci. 34
450 (2) : 255-271. Available from https://doi.org/10.1016/j.jas.2006.05.002
451
452 Fasola, M., Bogliani, G., Saino, N., and Canova, L. 1989. Foraging, feeding and time-activity
453 niches of eight species of breeding seabirds on the coastal wetlands of the Adriatic Sea. Bolletino
454 di zoología, 56 : 61–72. Available from https://doi.org/10.1080/11250008909355623
455
456 Fernández-Jalvo, Y., and Andrews, P. 2016. Atlas of taphonomic identifications. Vertebrate
457 Paleobiology and Paleoanthropology Series, Springer. 359p. doi: 10.1007/978-94-017-7432-1
458
Page 21 of 39
https://mc06.manuscriptcentral.com/cjz-pubs
Canadian Journal of Zoology
Draft
22
459 Frontin, D. 2017. Economie de pêche au Mésolithique et diversité piscicole à l’Holocène ancien
460 dans le bassin hydrographique du Doubs. Unpublished PhD thesis, Paris I Panthéon-Sorbonne
461 University, Paris (France).
462
463 González-Solís, J., Oro, D., Pedrocchi, V., Jover, L., and Ruiz, X. 1997. Trophic niche width and
464 overlap of two sympatric gulls in the southwestern mediterranean. Oecologia, 112 : 75–80.
465 Available from https://doi.org/10.1007/s004420050285
466
467 Guallart Furió, J., and Afán Asensio, I. 2013. Los sistemas naturales en el archipiélago de las
468 islas Chafarinas. Aldaba, 37 : 39-94.
469
470 Guillaud, E., Béarez, P., Denys, C., and Raimond, S. 2017. New data on fish diet and bone
471 digestion of the Eurasian otter (Lutra lutra) (Mammalia: Mustelidae) in central France. The
472 European Zoological Journal, 84(1) : 226–237. Available from
473 https://doi.org/10.1080/24750263.2017.1315184
474
475 Jones , A.K.G. 1986. Fish bone survival in the digestive system of the pig, dog and man: some
476 experiments. Edited by D. C. Brinkhuizen and A. T. Clason. Oxford: BAR International
477 Archaeopress Series 294 : 53-61.
478
479 Le Gall, O. 1999. Ichtyophagie et pêches préhistoriques. Quelques données de l’Europe
480 occidentale. Unpublished Doctorat d'état thesis, Bordeaux I University, Bordeaux (France).
481
Page 22 of 39
https://mc06.manuscriptcentral.com/cjz-pubs
Canadian Journal of Zoology
Draft
23
482 López, H., Pérez, A.J., Rumeu, B., and Nogales, M. 2016. Trophic strategies of Yellow-legged
483 Gull Larus michahellis on oceanic islands surrounded by deep waters. Bird Study, 63(3) : 337-
484 345. doi: 10.1080/00063657.2016.1194804
485
486 Matias, R., and Catry, P. 2010. The diet of Atlantic Yellow legged Gulls (Larus michahellis
487 atlantis) at an oceanic seabird colony: estimating predatory impact upon breeding petrels. Eur. J.
488 Wildl. Res. 56 : 861–869. Available from https://doi.org/10.1007/s10344-010-0384-y
489
490 Morales, A. in press. Review of “People with Animals. Perspectives and Studies in
491 Ethnozooarchaeology". Edited by L.G. Broderick. Oxbow Books. Orbis Terrarum
492
493 Moreno, R., Jover, L., Munilla, I., Velando, A., and Sanpera, C. 2010. A three-isotope approach
494 to disentangling the diet of a generalist consumer: the yellow-legged gull in northwest Spain.
495 Mar.Biol. 157 : 545–553. Available from https://doi.org/10.1007/s00227-009-1340-9
496
497 Nicholson, R.A. 1991. An investigation into variability within archaeologically recovered
498 assemblages of faunal remains: The influence of pre-depositional taphonomic factors.
499 Unpublished PhD thesis, York University, York (UK).
500
501 Oro, D., Pradel, R., and Lebreton, J.D. 1999. Food availability and nest predation influence life
502 history traits in Audouin’s Gull, Larus audouinii. Oecologia, 118 : 438–445.
503
Page 23 of 39
https://mc06.manuscriptcentral.com/cjz-pubs
Canadian Journal of Zoology
Draft
24
504 Poplin, F. 1976. A propos du Nombre de Restes et du Nombre d’Individus dans les échantillons
505 d’ossements. Cahiers du Centre de Recherches Préhistoriques, 5 : 61–74.
506
507 Ramos, R., Ramírez, F., Sanpera, C., Jover, L., and Ruíz, X. 2006. Feeding ecology of Yellow-
508 legged Gulls in four colonies along the western Mediterranean: an isotopic approach. J. Ornithol.
509 147 : 235–236.
510
511 Ramos, R., Ramírez, F., Sanpera, C., Jover, L., and Ruiz, X. 2009. Diet of Yellow-legged Gull
512 (Larus michahellis) chicks along the Spanish Western Mediterranean coast: the relevance of
513 refuse dumps. J. Ornithol. 150(1) : 265-272. Available from https://doi.org/10.1007/s10336-008-
514 0346-2
515
516 Reitz, E.J., and Wing, E.S. 2008. Zooarchaeology. Second edition. Cambridge University Press
517 (Cambridge).
518
519 Russ, H. 2010. The Eurasian eagle owl (Bubo bubo): a fish bone accumulator on Pleistocene cave
520 sites? Journal of Taphonomy, 8 : 281-290.
521
522 Russ, H., and Jones, A.K.G. 2011. Fish remains in cave deposits; how did they get there? Cave
523 and karst science, 38(3) : 57-60.
524
525 Russ, H. 2016. To fish or not to fish? Using observations of recent hunter-gatherer fishing in the
526 interpretation of Late Pleistocene fish bone assemblages. In People with Animals: Perspectives
Page 24 of 39
https://mc06.manuscriptcentral.com/cjz-pubs
Canadian Journal of Zoology
Draft
25
527 and Studies in Ethnozooarchaeology. Edited by L.G. Broderick. Oxbow Books Oxford. pp. 87-
528 102.
529
530 Tercerie, S., Béarez, P., Pruvost, P., Bailly, N., and Vignes-Lebbe, R. 2016. Osteobase. World
531 Wide Web electronic publication. [en ligne]. Available from http://osteobase.mnhn.fr/ [cité le 16
532 avril 2018]
533
534 Varela, J.M., and De Juana, E. 1986. The Larus cachinnans michahellis colony of Chafarinas
535 islands. In Mediterranean Marine Avifauna. Edited by NATO ASI Series, Mediterranean Marine
536 Avifauna. MEDMARAVIS and X. Monbailliu. Springer-Verlag Berlin Heidelberg G. 12 : 231-
537 244
538
539 Vidal, E., Medail, F., and Tatoni, T. 1998. Is the yellow-legged gull a superabundant bird species
540 in the Mediterranean? Impact on fauna and flora, conservation measures and research priorities.
541 Biodivers. Conserv. 7 :1013–1026. Available from https://doi.org/10.1023/A:1008805030578
542
543 Villa, P., and Mahieu, E. 1991. Breakage patterns of human long bones. J. Hum. Evol. 21 : 27–
544 48. doi: 10.1016/0047-2484(91)90034-S.
545
546 Votier, S.C., Bearhop, S., Ratcliffe, N., and Furness, R.W. 2001. Pellets as indicators of diet in
547 Great skuas Catharacta skua. Bird Study, 48 : 373-376. doi:10.1080/00063650109461237
548
Page 25 of 39
https://mc06.manuscriptcentral.com/cjz-pubs
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549 Witt, H.H., Crespo, J., De Juana, E., and Varela, J.M. 1981. Comparative feeding ecology of
550 Audouin’s gull Larus audouinii and the herring gull L. argentatus in the Mediterranean. Ibis, 123
551 : 519-526.
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553 Figure 1. Location of sites mentioned in the text.
554 Figure 2. Pellet of Yellow-legged Gull.
555 Figure 3. Modification of a precaudal vertebra of Anguilla anguilla (scanning electron
556 microscope).
557 Figure 4. Degrees of digestion. a) Undigested Boops boops, b) Sardine bones (loss absent); c)
558 Precaudal vertebra of sardine (minimal digestion); d) Caudal vertebra of sardine (moderate
559 digestion); e) Sardine vertebra exhibiting intensive digestion; f) and g) From the same pellet, two
560 patterns of digestion of precaudal vertebra of eel (lack of and heavy digestion); h) and i) From the
561 same pellet, two patterns of digestion of opercula of sardine (lack of and moderate digestion).
562 Figure 5. Skeletal elements before and after digestion in Yellow-legged gull pellets (Common
563 carp skeleton, modified from Tercerie et al. 2016 (osteobase.mnhn.fr) and Archaeological Fish
564 Resource (http://fishbone.nottingham.ac.uk/). For abbreviations see Table V.
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566 Table I. Number of identified remains from pellets of Yellow lugged gull. NISP: number of identified
567 specimens; (%): percentage of identified specimens
Congreso IslandNISP (%)
Rey IslandNISP (%)
TotalNISP
Total%
Fish 1505 (90.2) 1097 (97.9) 2602 93.3
Birds 87 (5.2) 7 (0.6) 94 3.4
Mammals 29 (1.7) 9 (0.8) 38 1.4
Seeds 15 (0.9) - 15 0.5
Crustaceans 10 (0.6) - 10 0.4
Molluscs 5 (0.3) - 5 0.2
Insects - 4 (0.4) 4 0.1
Rodents 1 (0.1) 3 (0.3) 4 0.1
Unidentifed remains 17 (1.0) - 17 0.6
Total 1669 (60) 1120 (40) 2789 100
568
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570 Table II. Number of identified and unidentified remains per Yellow lugged gull pellet. NISP: number of
571 identified specimens; (%): percentage of identified specimens.
Pellets Skeletal remainsIdentifiedNISP (%)
UnidentifiedNISP (%)
4 5 - 5 (0.2)
6 1 1 (0.04) -
9 1 1 (0.04) -
14 13 12 (0.5) 1 (0.04)
19 18 18 (1) -
29 3 - 3 (0.1)
30 43 43 (2) -
48 103 79 (3) 24 (1)
50 15 15 (1) -
52 6 2 (0.1) 4 (0.2)
56 4 4 (0.2) -
66 1 1 (0.04) -
69 10 10 (0.4) -
71 51 48 (2) 3 (0.1)
75 118 98 (4) 20 (1)
82 1 1 (0.04) -
83 121 110 (4) 11 (0.4)
84 99 99 (4) -
86 9 9 (0.3) -
101 1 1 (0.04) -
104 13 13 (0.5) -
110 16 16 (1) -
119 13 8 (0.3) 5
121 76 76 (3) -
122 384 370 (14) 14 (1)
128 14 - 14 (1)
142 15 - 15 (1)
144 1 1 (0.04) -
146 1 - 1 (0.04)
156 5 5 (0.2) -
159 10 10 (0.4) -
161 138 124 (5) 14 (1)
170 194 177 (7) 17 (1)
Cong
reso
isla
nd
173 2 2 (0.1) -
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Total 1505 1354 (52) 151 (6)
43 1 1 (0.04) -
46 11 11 (0.4) -
90 602 160 (6) 442 (17)
93 114 94 (4) 20 (1)
94 5 5 (0.2) -
95 69 47 (2) 22 (1)
97 42 34 (1) 8 (0.3)
182 2 2 (0.1) -
184 154 98 (4) 56 (2)
227 25 25 (1) -
276 1 1 (0.04) -
A 23 23 (1) -
B 24 24 (1) -
Rey
islan
d
D 24 24 (1) -
Total 1097 549 (21) 548 (21)
General total 2602 1903 (73) 699 (27)
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573 Table III. Number of identified remains and the minimum number of individuals per species and per pellets of Yellow lugged gull. 574
Anguillidae Carangidae Clupeidae Engraulidae Merlucciidae Serranidae SparidaePellets Anguilla
anguillaTrachurustrachurus
Sardinapilchardus
Sardinellaaurita
Engraulisencrasicolus
Merlucciusmerluccius
Epinephelussp.
BoopsBoops
Diplodussargus
Lithognathusmormyrus
Pagellusacarne
Pagelluserythrinus
Pagruspagrus
Sarpasalpa
4 - - - - - - - - - - - - - -6 - - - 1 (1) - - - - - - - - - -9 - - - - - - - - - - - - 1 (1) -
14 - - 12 (1) - - - - - - - - - - -19 - - - - - - - - - - - - 18 (1) -29 - - - - - - - - - - - - - -30 - - - - - - - - - - 43 (1) - - -48 - - 79 (1) - - - - - - - - - - -50 - - 4 (1) - - - - - - - 11 (1) - - -52 - - - - - - - 2 (1) - - - - - -56 - - 1 (1) - - - - 3 (1) - - - - - -66 - - 1 (1) - - - - - - - - - - -69 - 8 (1) 1 (1) - 1 (1) - - - - - - - - -71 - - 48 (1) - - - - - - - - - - -75 - - 98 (2) - - - - - - - - - - -82 - - 1 (1) - - - - - - - - - - -83 - - 110 (2) - - - - - - - - - - -84 - - 99 (2) - - - - - - - - - - -86 - - 5 (1) - - - - - - 4 (1) - - - -
101 - - - - - - - 1 (1) - - - - - -104 - - 8 (1) - - - 1 (1) - - 3 (1) 1 (1) - - -110 - - 16 (1) - - - - - - - - - - -119 8 (1) - - - - - - - - - - - - -121 - - - - - - - - - - - - - 76 (1)122 - - 370 (6) - - - - - - - - - - -128 - - - - - - - - - - - - - -142 - - - - - - - - - - - - - -144 - - - - 1 (1) - - - - - - - - -146 - - - - - - - - - - - - - -156 1 (1) - - - - - - - - - 4 (1) - - -159 - - - - - 10 (1) - - - - - - - -161 - 1 (1) 118 (2) - - 5 (1) - - - - - - - -170 - - 177 (3) - - - - - - - - - - -
Cong
reso
isla
nd
173 - 2 (2) - - - - - - - - - - - -Total 9 11 1148 1 2 15 1 6 - 7 59 - 19 76MNI 2 3 28 1 2 2 1 3 - 2 4 - 2 1
43 - - 1 (1) - - - - - - - - - - -
Re y
46 - - 11 (1) - - - - - - - - - - -
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90 31 (1) - 129 (6) - - - - - - - - - - -93 - - 94 (5) - - - - - - - - - - -94 - 1 (1) 4 (1) - - - - - - - - - - -95 - - 47 (3) - - - - - - - - - - -97 - - 32 (2) - - - - - 2 (1) - - - - -
182 - - 1 (1) - - - - - - - - 1 (1) - -184 - - - - 98 (4) - - - - - - - - -227 17 (1) - 8 (1) - - - - - - - - - - -276 1 (1) - - - - - - - - - - - - -
A - 23 (1) - - - - - - - - - - - -B - - - - - - - 24 (1) - - - - - -
i s l a n dD - - - - - - - 24 (1) - - - - - -Total 49 24 327 - 98 - - 48 2 - - 1 - -MNI 3 2 21 - 4 - - 2 1 - - 1 - -
General total 58 35 1475 1 100 15 1 54 2 7 59 1 19 76MNI total 5 5 49 1 6 2 1 5 1 2 4 1 2 1
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576 Table IV. Percentage and classes of digestion for fish taxon by number of remains (NISP) and
577 percentage
Total remainsnumber
Bone lossabsent
Minimal digestion
Moderatedigestion
Heavy digestion
Extremedigestion
Taxon NISP NISP % NISP % NISP % NISP % NISP %
Anguillidae 58 - - 32 1,68 9 0,47 17 0,68 4 0,21
Carangidae 35 - - 10 0,53 16 0,84 9 0,47 - -
Clupeidae 1476 45 2,36 76 3,99 388 20,39 967 32,48 349 18,34
Engraulidae 100 - - 1 0,05 2 0,11 97 5,1 - -
Merlucciidae 15 - - - - - - - - 15 0,79
Serranidae 1 1 0,05 - - - - - - - -
Sparidae 218 18 0,95 54 2,84 46 2,42 50 2,63 50 2,63
578
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580 Table V: Number of identified specimens (NISP) by bones and fish family in the Yellow-legged gull 581 pellets.582
583
Abbrevation Bones Anguillidae Carangidae Clupeidae Engraulidae Merlucciidae Serranidae Sparidae TOTAL
ar Articular 1 5 8 14
boc Basioccipital 3 1 1 5
bpq Basipterygium 2 2
c Caudal vertebra 37 3 343 65 9 1 458
ceh Ceratohyal 5 5
co Coracoïd 2 2
cl Cleithrum 1 11 2 2 16
dn Dentary 4 11 15
eph Epihyal 4 1 4 9
fr Frontal 2 2
hy Hyomandibula 1 9 2 12
iop Interopercle 2 1 3
mx Maxilla 1 1 2 1 9 14
neu Neurocranium 1 1
op Opercle 13 13
oto Otolith 5 2 7
pl Palatine 1 1
psp Parasphenoid 2 1 1 4
pha Pharyngeal bone 1 1
ptp Posttemporal 5 5
pc Precaudal vertebra 14 303 29 6 5 357
pmx Premaxilla 10 10
pu Preural vertebra 22 22
pop Preopercle 9 2 11
qd Quadrate 1 1 2 4
ec Scale (unidentified) 756
sc Scapula 2 2
sop Subopercle 2 1 3
scl Supracleithrum 2 2
ub Unidentified bones 2 7 10 1 54 74
ver Vertebra (unidentified) 72
vo Vomer 1 1
TOTAL 58 35 1476 100 15 1 218
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Figure 1. Location of sites mentioned in the text.
151x148mm (300 x 300 DPI)
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Figure 2. Pellet of Yellow-legged Gull.
203x148mm (300 x 300 DPI)
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Figure 3. Modification of a precaudal vertebra of Anguilla anguilla (scanning electron microscope).
200x170mm (300 x 300 DPI)
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Figure 4. Degrees of digestion. a) Undigested Boops boops, b) Sardine bones (loss absent); c) Precaudal vertebra of sardine (minimal digestion); d) Caudal vertebra of sardine (moderate digestion); e) Sardine vertebra exhibiting intensive
digestion; f) and g) From the same pellet, two patterns of digestion of precaudal vertebra of eel (lack of and heavy digestion); h) and i) From the same pellet, two patterns of digestion of opercula of sardine (lack of
and moderate digestion).
208x313mm (300 x 300 DPI)
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Draft
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Canadian Journal of Zoology