Raptor Breeding season report for Pinnacles National Monument - 2006

Emmons, Gavin

The 2006 breeding season was the 20th year of raptor monitoring at Pinnacles National Monument. Field observations began 10 January 2006 and ended 8 August 2006. Pinnacles National Monument (PNM) provides a diverse habitat for numerous cliff-nesting raptors, including sensitive species such as prairie falcons (Falco mexicanus) and golden eagles (Aquila chrysaetos), as well as a spectacular array of summits and cliff-wall routes for rockclimbers. Therefore, the behavioral and physical effect that climbers and off-trail hikers have on cliff-nesting raptors is studied. The 2006 raptor-breeding season was successful for prairie falcons. Fifteen territorial falcon pairs were documented this year with 14 pairs actively nesting. Thirty-five prairie falcons hatched, with 30 possible fledglings confirmed. Four nests failed (3 likely due to predation and 1 to eggs failing to hatch) and 1 pair occupied a territory without nesting for the season. A peregrine falcon (Falco peregrinus) pair successfully nested and fledged 3 young in the Hawkins territory, marking the second consecutive year that a successful peregrine falcon nesting effort has been documented at PNM in the last 48 years. Golden eagles were observed throughout the park. Six nests in 4 known territories in the park were not occupied this year. One known nest in the Eucalyptus Grove territory outside of the park produced 2 eaglets. Fledging was unconfirmed but likely for both. The 2006 breeding season was particularly successful for additional raptor species nesting in the park, with 60 nests representing 13 raptor species confirmed this year, easily the highest number ever documented in a single season. The first active nests recorded during the raptor monitoring project for long-eared owls (Asio otus) and for white-tailed kites (Elanus leucurus) were documented this year, and 3 breeding records (including 2 active nests) for turkey vultures (Cathartes aura) represented the first confirmed in the park in 22 years. Five long-eared owl breeding records – including 3 nests – produced 13 hatchlings, with 10 fledglings likely and 8 confirmed. Five white-tailed kite nests produced 17 hatchlings and 14 fledglings, with 4 more fledglings documented in 2 additional breeding records. Other nesting raptor species documented in the park included red-tailed hawks (Buteo jamaicensis), red-shouldered hawks (Buteo lineatus), American kestrels (Falco sparverius), Cooper’s hawks (Accipiter cooperii), sharp-shinned hawks (Accipiter striatus), barn owls (Tyto alba), and great-horned owls (Bubo virginianus). 2006 also marked the third year that captive-bred California condors (Gymnogyps californianus) were active and free-flying at PNM, with up to 13 condors active from Grassy Canyon to the High Peaks throughout the season. Condors were aggressively stooped by territorial raptors including peregrine and prairie falcons, on numerous occasions. Condors were also observed displacing turkey vultures, a bald eagle, and corvids from the Grassy Canyon feeding site.

Raptor Breeding season report for Pinnacles National Monument - 2006

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