Idaho Bird Records Committee Rarities Report Form

Rare Bird Report #: 29-B-07

Species: Red-shouldered Hawk

(composite report of 8 sightings between 1995-2004)

Reporter: Jay Carlisle

6105 Kirkwood Rd

Boise, ID 83709

jaycarlisle@boisestate.edu

Other Observers: many Idaho Bird Observatory hawk migration counters experienced with raptor identification including myself, Craig Fosdick, Ryan Brady, Justin Barrett, Dusty Perkins, and more

Date Report Prepared: 12-5-06

Date Sightings Occurred:

1997: Sept 28, Oct 18

1998: Sept 23

2001: Oct 5

2002: Sept 28

2003: Sept 28, Sept 29

2004: Sept 19

Locality of Observation: Lucky Peak, Boise Foothills, Ada Co.; an Idaho Bird Observatory migration study site

Habitat: north-south trending ridgeline with a patchy mosaic of shrubsteppe, mountain deciduous shrubland, and conifer forest

Conditions: Most Red-shouldered Hawks (as with most species observed at the site) have been seen during high pressure weather and light to moderate winds. Observers have been well-trained in in-flight raptor identification and have used 8x and 10x binoculars; occasionally a spotting scope (20-60 zoom) was used to confirm ID of distant birds. At least 2 observers were present during all observations.

Did you take notes? no

Did you consult a field guide or other reference work? Before, during, and after the observations. Observers used the following field guides to prepare for the season and to study up during the season.

What guide(s) or reference(s) did you consult?

‘Hawks in Flight’ by Dunne, Sibley, and Sutton; ‘A Field Guide to Hawks of North America’ by Clark; Sibley & National Geographic

Description: The major fieldmarks used to identify migrating Red-shouldered Hawks were: relatively long wings; a buffy (immatures) to whitish (adults) pale crescent-shaped pale patch at base of outer primaries; broad tail with many alternating dark and light bands (2 shades of brown in immatures; black and white in adults); rapid flapping; and smaller size in relation to Red-tailed Hawks (the common Buteo that migrates past the sight).

Behavior: All birds were seen as active migrants passing by the observation point at Lucky Peak. Most, if not all, Red-shouldered Hawks were seen in a combination of flapping, soaring, and gliding flight. Fieldmarks are easiest to see when soaring and the rapid flapping behavior is unlike other Buteos and more reminiscent of a smaller Accipiter.

A note on timing patterns and subspecies: While certainly a rarity at the site and in Idaho, there is a fairly uniform pattern of sightings occurring between mid-September (earliest on 9/19) and mid-October (latest on 10/18), with four of the sightings occurring on either 9/28 or 9/29. Most individuals were deemed to be immatures of the western elegans subspecies (including the bird on Sept 28, 1997 which I saw well, with many observers, for several minutes) based on more black and white in feathers and rufous in wing linings. However, the bird seen on Sept 28, 2002, viewed by many observers (including Ryan Brady and myself, both with extensive experience with the species), was an immature of the eastern (nominate) lineatus subspecies based on more brownish tones to the flight feathers, distinct streaking on chest, and very little rufous on wing linings.

How and when did you positively identify the bird, and what clinched the identification for you? Each bird was identified by a combination of the features mentioned in the Description section above, especially the rapid flapping behavior, pale crescent-shaped patches in outer wings, and banding on the tail.

How did you eliminate similar species, and what were they? Possibilities include Red-tailed Hawk, Swainson’s Hawk, Broad-winged Hawk, and Northern Goshawk. Red-tails and Swainson’s are larger and Broad-winged and Swainson’s Hawks have more tapered wings. Lighter morphs of Red-tailed Hawk show an obvious dark area on the patagial area of the underwings. Swainson’s Hawk wings tend to show a very broad dark trailing edge to the underwing. Broad-winged Hawks have fewer tail bands; lack the crescent-shaped light patch on the inner portions of the outer primaries; have narrow, dark trailing edges to underwings; and have shorter wings. Lastly, Northern Goshawks, possibly most similar in size to Red-shouldered Hawk, has a longer tail (never with white bands) and a distinct pale supercilium in all plumages. On the first Red-shoulder recorded at the site (Sept 28, 1997), I spotted the bird at a distance and initially identified it as a probable Northern Goshawk based on size and shape. It glided down the ridge to give a much closer view and then turned to begin a series of circles combining flapping and soaring during which time the rapid flapping, pale crescents, and Buteo-length tail (shorter than a goshawk) gave away the identification.

Experience with this species (and similar species): In total, we have had 8 sightings of Red-shouldered Hawk from this site as well as one bird captured and banded at our Boise Peak banding site (see separate report). I personally have seen well over 100 Red-shouldered Hawks in many US states (CT, CA, SD, ID, etc.) as well as in Mexico; I have seen 2 of the 8 Lucky Peak birds. Hawk counters annually see well over 500 Red-tails, between 25-100+ Swainson’s Hawks, 25-50+ Northern Goshawks, and an average of just under 18 Broad-wings. I personally have observed many thousands of the three Buteo species all across the US (western/central US for Swainson’s) and in Latin America and I have observed hundreds of Northern Goshawks in many states and in all seasons.

General birding experience: extensive; 14+ years in US and Latin America

Were photo(s), video, and/or audio obtained by you? (If yes, please include or attach) No.