[cobirds] cuckoo ID

Somehow, the bulk of text composed for my post about cuckoo ID did not appear in what got send out. 

Basically what I meant to send out with the four photos was that ID of cuckoos at this time of year can be compounded by the presence of young "black-billed" yellow-billed cuckoos.

I also wanted to say I am NOT questioning here the ID of black-billed cuckoos recently reported by both John Drummond and Steve Mlodinow.  Their reports/photos are solid.

Fall Webworms (Hyphantria cunea) are present at Tempel's Grove and are known to be prominent in the late summer diet of cuckoos.  They live within webs enlarged to include the leaves on which they feed.  At this time of year the webs can be multiple feet across.  They leave the webs, however, after feeding for a period of several weeks to pupate and overwinter in the leaf litter on the ground.  This is when they are most vulnerable to bird predation.  The true tent caterpillars often mentioned in the diet of cuckoos are in the genus Malacosoma (we have five species in CO) are late spring-early summer caterpillars which build smaller, whiter webs they use as home bases at night, venturing out to feed "unprotected" during the day.

Grasshoppers, such as the two-striped shown on the other email, were being fed to the young dependent cuckoo by an adult yellow-billed.  They are also mentioned in the BNA account of cuckoos as being prominent in cuckoo diets.

Dave Leatherman

Fort Collins