IBRC 35-B-10

Idaho Bird Records Committee
Rarities Report Form

Species: Black-billed Cuckoo

Reporter: Jay Carlisle

989 W. Sherwood, Boise, ID 83706

jaycarlisle@boisestate.edu

Other Observers: Heidi Ware

Date Report Prepared:  6-7-10 (from notes same day as sighting)

Date Sighting Occurred:  5-23-10

Locality of Observation: Boise, Ada County

Habitat: urban/suburban – major street (State St) with some big trees in housing neighborhoods within 1 block on either side

Conditions:  mostly clear; the bird was about 40-50m in front of us as we drove west to east on State Street and the sun was behind us.  We used no optics.

Did you take notes?  no

Did you consult a field guide or other reference work?  yes

What guide(s) or reference(s) did you consult? National Geographic & Sibley as well as online photos of in-flight cuckoos (Google image search)

Description:  At about 740pm while driving east on State Street, we observed a cuckoo fly N across State Street in the area just west of 31st Street. It was a naked-eye (drive-by) sighting. 

Here's what we saw:

• an approximately robin-sized bird but with proportionately long and slender wings & tail
• tail was swept back and appeared rectangular in shape (i.e., squared off at end); longer than on a robin or dove
• overall coloration was brownish above; whitish below - a hint of grayish on the head

Neither of us noted any details of the bill.

Behavior:  The bird flew quickly N across State Street and disappeared behind some trees.

How and when did you positively identify the bird, and what clinched the identification for you?  After getting over my shock at observing a cuckoo of any species in Boise, I realized that we could see no rufous in the flight feathers (something that is normally visible in a Yellow-billed when in flight) ... suggesting a Black-billed Cuckoo.  The sun was behind us affording very good light for viewing.  Thus, I expect that we should have been able to pick out rufous in the wings on a Yellow-billed.

How did you eliminate similar species, and what were they?  The only similar appearing species is the Yellow-billed Cuckoo which has bright yellow in the bill, extensive rufous coloration in the primaries, and more obvious black & white near the tips of the tail feathers.

I’ll note that the rapid flight was reminiscent of Mourning Dove (although the cuckoo flew in an unswerving manner) … in fact, maybe 30 sec later a dove provided a similar fly-by and I asked Heidi, “Are you sure it wasn’t just a dove that fooled us?” and she adamantly said, “No.  The tail and wings were different.”  When I asked for elaboration, she described the more squared-off (as opposed to pointed) tail and more slender & rectangular wings.

To be honest, I’m still not comfortable with the very brief nature of the sighting (and not very excited about having my ‘state’ Black-billed come in such a way) but I don’t know what else it could have been.  And, Heidi’s observations of the bird plus communication with several birders helped me to feel more confident about it.

Experience with this species (and similar species): I have seen multiple 10s of both cuckoo species in several states, especially in South Dakota and Louisiana, and I have seen Yellow-billed on 2 previous occasions in Idaho.  I’ve seen Yellow-billed in flight on several occasions and have always seen the rufous primary coloration in good light.

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