Northern Goshawk Finding 2001. 7. 3.¢  The northern goshawk ( Accipiter gentilis ) was...

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Transcript of Northern Goshawk Finding 2001. 7. 3.¢  The northern goshawk ( Accipiter gentilis ) was...

  • Northern Goshawk Finding

    June 1998

    Note: The pagination and appearance of this electronic version of the Northern Goshawk Finding may vary slightly from the original printed document. However, the content of this version is the same as the printed version.

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    consideration of a listing action substantially broader in scope than the petition under review at that time, the Service informed the coalition that their request for an amendment would be considered as a separate, new petition.

    On January 7, 1992, the Service published a finding that the July 1991, petition did not present substantial information to indicate that the goshawk in the petitioned region (Utah, Colorado, New Mexico and Arizona) constituted a listable entity (57 FR 546). However, the Service concluded that the petition presented substantial information indicating that northern goshawk population declines and loss or modification of habitat may be occurring. Therefore, the Service announced in a separate Federal Register notice (January 7, 1992; 57 FR 544) the initiation of a status review for the northern goshawk throughout its range in the United States. The January 1992 status review specifically solicited information to evaluate the potential for “distinct population segments” within the range of the northern goshawk in North America.

    On June 25, 1992 (57 FR 28474), the Service published a 90-day finding that the September 1991, petition did not present substantial information to indicate that the northern goshawk in the western United States was a listable entity. The Service found that the petition presented no evidence of reproductive isolation or genetic differentiation between the goshawk in the west and the goshawk in the eastern United States, and that goshawk habitat was contiguous from the western United States to the eastern United States through Canada. The petitioners subsequently filed suit in Federal District Court in Phoenix, Arizona to have the Service’s finding set aside. On February 22, 1996, United States District Judge Richard M. Bilby found the Service’s June 25, 1992, finding to be arbitrary and capricious and remanded it to the Service for a new 90-day determination.

    On June 6, 1996 (61 FR 28834), the Service published a notice vacating the petition finding of June 25, 1992, and published a new 90-day finding that the petition to list the northern goshawk in the western United States had not presented substantial information that the petitioned action may be warranted. The Service determined that since the entity petitioned for listing was comprised of more than one subspecies it did not meet the definition of a distinct vertebrate population segment as defined in the National Marine Fisheries Service and Fish and Wildlife Service Final Policy Regarding the Recognition of Distinct Vertebrate Population Segments under the Endangered Species Act (DPS policy; February 7, 1996; 61 FR 4722).

    The petitioners again filed a suit in Federal District Court to have the Service’s June 1996, finding set aside. On June 6, 1997, Judge Bilby found the June 1996, finding to be arbitrary and capricious, and remanded it to the Service for another 90-day finding. On August 19, 1997, Judge Bilby clarified that the decision on remand was to be made using the Service’s DPS policy without the “one subspecies” rule that the Service had relied on in making its June 6, 1996, finding. In addition, on August 22, 1997, the petitioners amended their petition to seek listing of northern goshawks west of the 100 meridian in the contiguous 48 states.th

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    Figure 1. Northern Goshawk Status Review Area with Assessment Area boundaries

    Northern Goshawk Status Review Team

    June 1998

    100th Meridian

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    Forested Area States Assessment Areas

    Northern Goshawk Status Review Team

    June 1998

    Figure 2. Forested Habitat in the Status Review Area

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    On September 29, 1997, the Service published a 90-day finding (62 FR 50892) that the petition provided substantial information indicating that the listing of the northern goshawk as threatened or endangered in the contiguous United States west of the 100 meridian may be warranted. Atth

    that time, the Service initiated a Status Review for the northern goshawk. Figure 1 illustrates the geographic scope of the Status Review area. For purposes of analysis only, the Service’s Status Review Team broke the petitioned area into 6 assessment areas; these areas do not reflect potential distinct population segments. Figure 2 illustrates the distribution of forested habitat in the Review Area.

    Life History

    Description The northern goshawk is the largest of the three accipiters of North America, possessing short, broad wings and a long, rounded tail. Females are larger than males, with total average length of about 61 centimeters (cm) (24 inches (in)) for females and 55 cm (22 in) for males. The wingspan for females is 105-115 cm (46 in) and for males is 98-104 cm (42 in) (Wood 1938, Squires and Reynolds 1997). Adults are gray above, blackish on the crown and side of head, with a bold, whitish streak over the eye. The underparts are light gray with fine horizontal vermiculations and fine vertical streaks. The tail is dark gray above, with several blackish bands; the tail tip is rounded and usually tipped with a white terminal band. Tail below is lighter gray with fluffy white undertail coverts (Squires and Reynolds 1997). Immatures (Palmer 1988, Johnsgard 1990, and Squires and Reynolds 1997) are a dark brown to brownish-black above with buffy white and cinnamon streaks. The underparts are a buff white, with cinnamon to brown streaking on the throat. The head is brown and usually has a narrow whitish streak over the eye. The dark brown tail has wavy dark brown bands with thin whitish borders that form a zigzag pattern. Undertail coverts are usually streaked, and not fluffy.

    Taxonomy The northern goshawk (Accipiter gentilis) was originally described by Linneaus. The northern goshawk is circumpolar in distribution, with two groups recognized worldwide: the palearctic gentilis group, consisting of several subspecies (A. g. gentilis, Europe to central Russia; A. g. buteoides, northern Europe and Asia; A. g. albidus, northeastern Siberia to Kamchatka; A. g. arrigoni, Sardinia and Corsica: A. g. schvedowi, southern Siberia, northern Japan, Chinese Mountains; and A. g. fujiamae, Honshu Island), and the nearctic atricapillus group consisting of A. g. atricapillus (Wilson 1812, type locality Philadelphia, Pennsylvania). The atricapillus group occurs over much of Alaska, Canada, and the mountains of the western and eastern United States. In addition to the main A. g. atricapillus subspecies, at least two other subspecies are currently, but variously, accepted--A. g. laingi (Taverner 1940, type locality Queen Charlotte Islands, British Columbia), and A. g. apache van Rossem (van Rossem 1938, type locality Chiricahua Mountains, Arizona), which occurs in the mountains of southeastern Arizona, southwestern New Mexico and northern Mexico (Wattel 1973).

    In addition to apache and laingi, two other subspecies have been described but are no longer

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    recognized. In 1874, Ridgeway (Baird et al. 1874) described a western goshawk (A. g. striatulus) based on differences in plumages of hawks in the western United States from the more eastern atricapillus form. In 1884, Nelson (1884) described A. g. henshawi from Lake County, Oregon and Calaveras County, California, on the basis of darker plumages than atricapillus.

    Taverner, 1940, showed the plumage differences of striatulus were associated with age of hawks and that striatulus was indistinguishable from atricapillus. He described A. g. laingi from the coastal islands of British Columbia on the basis of darker plumages, a characteristic of both the adult and juvenile plumages. Taverner (1940) also reported a gradient in plumage darkness from the lighter-colored mainland hawks to intermediate forms on Vancouver Island to the darkest hawks on the Queen Charlotte Islands.

    Van Rossem (1938) described the subspecies A. g. apache on the basis of longer wing chords and darker colors of six hawks collected in southern Arizona and Sonora and Jalisco in Mexico. The distinguishing characters of apache, as defined by van Rossem (1938), are “darker and more blackish (less bluish) dorsally even than Accipiter gentilis striatulus (Ridgeway) of the Pacific Northwest, the darkest of two previously described North American races; young with ventral streaking broader and darker than the young of striatulus (= atricapillus). Size largest among the North American races.” Van Rossem (1938) gives the range of apache as “extreme southeastern Arizona (Chiricahua Mountains), south through Sonora (Yecora) to Jalisco (Sierra de Nayarit).”

    Recognition of the apache subspecies is variable and a subject of current debate. It is recognized by Brown and Amadon (1968), Wattel (1973) and Snyder and Snyder (1991). However, apache was excluded from the American Ornithologists’ Union’s (AOU) Check-list of North American Birds 5 edition (1957). Because van Rossem (1938) originally descibed apache based on only 3th

    specimens, the validity of the subspecies is not accepted by most taxonomists. Hubbard (1992) presented evidence for retaining apache, however, the AOU still does not recognize it as a valid subspecies (AOU 1983). The Fish and Wildlife Service acknowledged the existence of apache as a subspecies in its 1992 administrative finding relativ