#: 74-B-07

Idaho Bird Records Committee Rarities Report Form

Species: Purple Martin

Reporter: Cliff Weisse, 4125 Beaver Springs Rd., Island Park, ID 83429, 208-558-7789, cliffandlisa@octobersetters.com

Other Observers: Darren Clark on 6/30

Date of Observation: June 29, 2007, about 4:00 pm

Date Report Prepared: July 1, 2007

Locality of Observation: Near Table Rock Mountain on the South Fork of the Snake River, upstream from Heise. Table Rock Mountain is the hill that Kelly Canyon Ski Area is on.

Habitat: Riparian

Conditions: Sunny with winds about 20 mph, distance as close as 0 yards (in flight directly overhead at unknown height), duration of sighting about 10 seconds, naked eye.

Did you take notes…

the same day? Yes

Did you consult a field guide or other reference work?

later the same day? Yes

What guide or reference did you consult?

Sibley Guide to Birds of North America

Description: Swallow-like bird seen in flight only and only from below. I was looking for White-throated Swifts that nest in the area and I saw this large-looking individual flying towards me over the water. There were Tree, Cliff, and Violet Green Swallows in the immediate area as well as White-throated Swifts. I was not able to make a direct comparison of size because there were no other birds close to this individual, but it appeared larger than the swallows I had been seeing all day. The wings were dark below, long, and pointed but not nearly as narrow proportionately as a swift. The breast was dark and grayish and the belly was pale whitish but not bright white like Tree Swallows and White-throated Swifts seen within five minutes of observing this individual. The breast color blended into the paler belly color with no sharply defined seperation. The tail was dark (contrasting with the pale undertail coverts), and the overall impression was of a long and narrow rear end of the bird (behind the wings) with a dark tip. The bird turned sharply and flared its tail once and it was clearly forked, deeper than any swallow except Barn Swallow and possibly Bank Swallow, but not as deeply forked as Barn Swallow and lacking the long narrow streamers of that species. The corners of the tail were sharply pointed. What really stands out to me now, after reviewing the drawings of swallows/swifts/Purple Martin in flight in Sibley, is the long, narrow, pale hind end of the bird.

Behavior: Foraging over the river. The bird flew similarly to swallows except it didn’t circle around over the water like the swallows. Instead it flew by and continued flying south until I lost sight of it against a distant ridge. I did not take note of the rate of wing beats. The wings were held straight out when it soared/glided, not folded back along the sides of the body. I saw it make one sharp turn, presumably to intercept a flying insect, very much like a swallow would.

How and when did you positively identify the bird, and what clinched the identification for you? My first impression was of a slightly larger bird than the swallows present. I immediately recognized that this was not a swift because of wing shape. The pattern of color on the underparts, dark breast with pale belly, did not fit any swallow. When I saw the forked tail I began to think this was a Purple Martin. I didn’t come to the conclusion that it was a Purple Martin until I saw a White-throated Swift (again with naked eye) about five minutes later. The stark white of the underparts of the swift, combined with wing shape, helped convince me of the ID of the Martin.

How did you eliminate similar species, and what were they? The only swallow that has a tail with similar shape, forked with pointed corners, is Bank Swallow which has white underparts in all plumages with a sharply defined dark band across the breast. Tree and Violet Green Swallows have stark white underarts and square tails. Northern Rough-winged Swallow has a similar pattern below but has a square tail and the dark coloration of the breast is more limited to the upper breast. Cliff Swallow has a square tail and sharply defined dark bib. Barn Swallow has entirely buff underparts with long, deeply forked tail and long narrow tail streamers. All swifts have long narrow wings. Black swift has entirely black underparts. The other three swifts have opposite color pattern below with breast paler than belly. The only other species of confusion I can think of is European Starling which has short tail and concolor underparts in all plumages.

Experience with this species: I have seen a few Purple Martins in MO, NJ, and WI. I spend 80-90 days per year on rivers as a fishing guide. This gives me the opportunity to study thousands of swallows annually and at close range without the aid of optics. As a result I feel my ability to ID swallows in flight with naked eye is very good or excellent.

General experience birding: 14 years

Were photo(s), video, and/or audio obtained by you? no