Warbling Vireo and brown-headed cowbird chick, Mammoth

Observers: Donna & Bob Willey
Email: basina@verizon.net
Verification: MONO
Remote Name:
Date: 07/26/2007
Time: 11:39 PM -0400

Hi everyone who loves birds; I have been away for awhile and now am back in Mammoth. Just prior to leaving I had been watching two black-headed grosbeaks on their nest. They fledged 3 chicks in 7 days; extremely fast but within their range. However, when the chicks left the nest they were hardly able to get around and the parents had to feed them and give them flying instructions. As I followed the chicks and parents around the aspen forest I found myself under a small aspen tree which had a vireo nest in it. The nest, beautifully made and attached tightly to a branch contained 3 chicks, just hatched. The parents were warbling vireos of 2 of the chicks, the 3rd chick unfortunately was a brown-headed cowbird. I left shortly after spotting the nest. Now one month later I ran into the WV parent feeding a rather large brownheaded cowbird. I am posting a few photos of the nest before the chick was fledged and of the parent warbling vireo with the cowbird chick taken today. Unfortunately there is no sign of the other 2 chicks and this saddens me. Quite frankly we know that brown-headed and bronze-headed cowbirds are predators of certain songbird species and the WV is one of these. I feel quite certain that the large cowbird probably pushed its competition from the nest and thus is the sole survivor and inheritor of the WV's parentage and bountiful feeding techniques. Hence, we are the spectators to what is called "brood parasitism." My husband says it is repulsive; I do not find it repulsive but it does sadden me. Our avian friends work so very hard to reproduce, they put such enormous effort into the act of reproduction and it is hard for us to see this little bird, so full of energy feeding and nurturing the very enemy of its own survival. Yet, this act of predation has been on-going for centuries and the species which are parasitized persist, as well as the parasitizer. So I again stand speechless at the magnitude of nature's bounty and tenacity.