NESTS, NEST CONSTRUCTION, VARIATION IN NESTS BASED ON SPECIES

Sort of an extension from Chapter 15, will want to know this information for Final.

After this we’ll look at some nests (exercise here) and do statistics for project.

Nests are used primarily for the raising of young Incubation of eggs Brooding of nestlings (altricial species)

There are a few species that build ‘dormatory’ nests for non-nesting purposes – we won’t worry about them Monk Parakeets (Myiopsitta monachus) in New Orleans do this

There are a few species where males build display nests that aren’t used – we won’t worry about them Carolina Wrens (Thryothorus ludovicianus) will do this

Focusing here on nests that are used during offspring production

NESTS

Birds lay eggs, eggs must be protected and incubatedNest structure and location important Guarding against nest

predators Guarding against nest

parasites Consistent incubation,

may assist in temperature regulation

NESTS

Nest cup helps facilitate contact between female and eggs, nest content helps retain warmth

Nest location and placement can vary strongly From tree tops and rocky

cliffs to underground or sitting on the water

Nest content can vary Sticks/twigs, grass, mud,

feathers, hair, barkAll this impacts nest

microclimate Strong evolutionary

impact

NESTS

The Wrinkled Hornbill (Aceros corrugatus) is a cavity nester

NESTS – NOT REALLY A NEST?

The Australian Brush Turkey (Alectura lathami) doesn’t build a classic nest, instead it’s a mound of rotting vegetation

Development and nesting behavior of this species considered to be very primitive

NESTS – WATER BASED

Pacific Loon (Gavia pacifica) nest above and Pied-billed Grebe (Podilymbus podiceps) nest at right

Both cases nests are built of rotting materials (warmth?) and barely above the water (safety). Most loons and grebes build nests like this.

NESTS – GROUND NESTS

Many species nest directly on the ground in nests that may be made of grass or twigs, sometimes just a scrape in the ground.

Snowy Owl (Bubo scandiacus) nest at left and a Brown Pelican (Pelecanus occidentalis) below

NOTE: big size differences in offspring

NESTS – GROUND NESTS

Northern Harrier (Circus cyaneus) nest at above left, King Eider (Somateria spectabilis) nest lower left, Laughing Gull (Leucophaeus atricilla) nest below.

Note that species that nest on the ground are often:Large speciesColony nestersFound in inaccessible areas

Cryptic in natureDangerous predators in their own right

NESTS – GROUND NESTS

Arctic Tern (Sterna paradisaea)

Royal Tern (Thalasseus maximus)

Burrowing Owl (Athene cunicularia)

Belted Kingfisher (Megaceryle alcyon)

NESTS – BURROW NESTS

Many cases the burrow was constructed by someone else, like a Gopher Tortoise

NESTS – CAVITY NESTS

Many species use cavities, some are primary cavity excavators (like the Red-headed Woodpecker, Melanerpes erythrocephalus) while others are secondary cavity dwellers (like the Scarlet Macaw, Ara macao)

NESTS – CAVITY NESTS

Great Horned Owl (Bubo virginianus)

Eastern Bluebird (Sialia sialis)

Prothonotary Warbler (Protonotaria citrea)

NESTS

NESTS - ARTIFICIAL

Some species will readily accept man-made cavitities

NESTS - ARTIFICIAL

Peregrine Falcons (Falco peregrinus) nest on open cliff faces, hunt in open areas. This has allowed them to adapt to human habitation and human supplied ‘cliff’ faces

NESTS

Classic nest found in tree or shrub

Materials used in nests can vary widely as well Nothing (or next to it), just

a ground scrape or a few sticks

Grass Twigs, sticks, and bark Mud

Construction can vary as well Classic round nest shape Hanging baskets More exotic

NESTS – MATERIALS

Mourning Doves (Zenaida macroura) build surprisingly scanty nests for such a substantial bird

NESTS - SPECIALTIES

Tailorbirds (Orthotomus sutorius) use a variety of grasses and plant fibers for the nest, and then have a unique construction

NESTS – SPECIALTIES

Barn Swallow (Hirundo rustica) nests, above, are made of mud and feathers, Monk Parakeets (Myiopsitta monachus), right, use grass to build large nest colonies

A swift nest made from saliva, will be used in bird’s nest soup

NESTS – SPECIALTIES

Chestnut-headed Oropendola (Psarocolius wagleri) nests are finely woven structures

Orchard Orioles (Icterus spurius) build a hanging basket type nest as well

NESTS

Most nests that one could see are going to be the stereotypical ‘nest’ Made of a collection of

materials (grass, twigs, bark, hair, feathers

An outer heavier layer An inner soft layer that

provides insulation and cushioning

Habitat used by the adult often dictates what type of nest you will see

Northern Cardinal (Cardinalis cardinalis)

Eastern Meadowlark (Sturnella magna)

NESTS

A precocial waterbird species like the Mallard (Anus patyrhynchos) can have a ground nest that is well camouflaged until hatching, then the hatchlings leave

Nest success varies with latitude, nest location, and species size and offspring hardiness Predation, starvation, adverse weather – big causes of

nesting failure

Nest success also varies with type of nest Cavity nesting species typically do better than open cup

nesters, or ground nesters

NESTS

Song Sparrow (Melospiza melodia) nestlings