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<\/p>\nFolks who dislike Brown Cowbirds for their\u00a0habit of\u00a0nest parasitism will likely appreciate this unique ‘revenge’ of the American Goldfinch. We’ll get into that soon but first some goldfinch photos I took yesterday morning.<\/p>\n
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1\/5000, f\/6.3, ISO 800, Canon 7D Mark II, Canon EF 500mm f\/4L IS II USM + EF 1.4 III Extender, not baited, set up or called in<\/em><\/p>\n I rarely post images of goldfinches, partly because I don’t photograph them at my feeders but also because I’ve seldom been able to get very close to them in wild situations recently. But yesterday in the Wasatch Mountains this handsome male allowed a close approach. He was on such a steeply\u00a0angled perch his body was sometimes\u00a0a little tilted so I decided not to\u00a0rotate the image to make him\u00a0vertical because this is the way he really\u00a0was.<\/p>\n I had pretty\u00a0good light on the bird but there was partially shaded vegetation in the background on the other side of the canyon so it’s quite dark back there.<\/p>\n <\/p>\n <\/p>\n 1\/4000, f\/6.3, ISO 800, Canon 7D Mark II, Canon EF 500mm f\/4L IS II USM + EF 1.4 III Extender, not baited, set up or called in<\/em><\/p>\n It’s fairly late in the breeding season, even for late-breeding goldfinches, so he wasn’t singing a lot but I did get a few singing poses.<\/p>\n <\/p>\n <\/p>\n 1\/3200, f\/6.3, ISO 800, Canon 7D Mark II, Canon EF 500mm f\/4L IS II USM + EF 1.4 III Extender, not baited, set up or called in<\/em><\/p>\n When these guys rouse they put their heart and soul into it, at least this one did. I didn’t get a catch light in this head-on shot but I couldn’t resist posting it anyway because his shaking transformed him into such a fluffball and I like the way it\u00a0flung his tail to one side.<\/p>\n <\/p>\n <\/p>\n 1\/4000, f\/6.3, ISO 800, Canon 7D Mark II, Canon EF 500mm f\/4L IS II USM + EF 1.4 III Extender, not baited, set up or called in<\/em><\/p>\n Here he’s beginning to recover from the rouse and I even got a catch light in a front view.<\/p>\n <\/p>\n <\/p>\n 1\/5000, f\/6.3, ISO 800, Canon 7D Mark II, Canon EF 500mm f\/4L IS II USM + EF 1.4 III Extender, not baited, set up or called in<\/em><\/p>\n And he hadn’t even sleeked down again before he resumed his singing.<\/p>\n Ok, what about this revenge thing?<\/p>\n <\/p>\n 1\/1600, f\/6.3, ISO 400, Canon 7D, Canon EF 500mm f\/4L IS II USM, not baited, set up or called in<\/em><\/p>\n As many of my readers know Brown Cowbirds are nest parasites. Adult females lay their eggs in the nests of other songbirds (they never build their own nests)\u00a0and the rightful owners of the nest unwittingly raise the youngsters as their own. Cowbirds are larger than many\u00a0of their songbird hosts\u00a0and their eggs hatch quickly and their offspring grow\u00a0very fast\u00a0so the chicks of the nest owners get little food and often don’t make it for various unpleasant reasons\u00a0– but the cowbird chicks thrive.<\/p>\n In this photo we see an adult Savannah Sparrow in Montana’s Centennial Valley\u00a0about to feed\u00a0a beak-full of insects to\u00a0a newly fledged cowbird chick it has unwittingly\u00a0raised. Yes, the size difference is dramatic and pretty silly looking.<\/p>\n Ok, here’s where the “revenge” factor enters the picture with goldfinches. Virtually all songbirds, even the strict\u00a0seed-eaters, switch to a partly or completely insectivorous diet during the breeding season because growing chicks need a lot<\/em> of protein. But goldfinches are almost strictly seed-eaters even during the breeding season, suggesting that they have adapted to obtaining sufficient protein from a seed diet. And that’s what they feed to their chicks, including parasitic cowbird chicks in their nests.<\/p>\n So, even though the cowbird chicks in goldfinch nests\u00a0hatch successfully their growth is retarded for lack of\u00a0the protein they require\u00a0and almost all of them die before they can leave the nest.<\/p>\n It’s almost like the goldfinches are saying “If you have the\u00a0unmitigated gall\u00a0to lay your eggs in my nest and make me feed your youngsters at the expense of my own\u00a0I’ll make sure your kids don’t survive”. That’s close enough to revenge for me, though of course it isn’t, not really.<\/p>\n Personally I don’t have a problem with the nest parasitism of cowbirds but I’m also comfortable with its lethal results for their chicks\u00a0when they parasitize goldfinch nests because it’s all natural.\u00a0But it does\u00a0make me wonder if, through behavioral adaptation, cowbirds will eventually learn to avoid parasitizing goldfinch nests and take their “business” elsewhere.<\/p>\n The ways of evolution are truly amazing.<\/p>\n Ron<\/p>\n <\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Folks who dislike Brown Cowbirds for their habit of nest parasitism will likely appreciate this unique “revenge” of the American Goldfinch. We’ll get into that soon but first some goldfinch photos I took yesterday morning.<\/p>\n![\"\"](\"https:\/\/featheredphotography.com\/blog\/wp-content\/uploads\/2018\/07\/american-goldfinch-6454-ron-dudley.jpg\" "\\"american-goldfinch-6454-ron-dudley\\"")
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