Скачать с ютуб Brown-Headed Cowbirds в хорошем качестве

Brown-Headed Cowbirds

Script: Brown-headed cowbirds are absolute bastards. They are bullies, negligent parents, parasites, murderous, and steal food from babies. Brown-headed cowbird parents sneak their eggs into other birds’ nests so that they don’t have to take care of their own children. Their children grow up faster than their step-siblings, and quickly hog all the food. They will steal it from their step- brothers and sisters, or just straight up kill them. Eventually they fly the nest as full grown brown-headed cowbirds---only to do the same with their children. You might think that the other would-be step-parents would learn not put up with this, and indeed they sometimes know how to identify brown-headed cowbird eggs and brown-headed cowbird chicks. But the ones that try to stop this egregious scheme suffer incredible harsh punishment. If they push the cowbird eggs out of their nest, the cowbird parent will wait until they are gone, and then murder their children. You might think that’s pretty bad, but it is even more nefarious than you might think. Killing those other chicks keeps the whole system in place on an evolutionary level. The bird step-parents that choose not to parent the intruder chicks, don’t have children. The bird step-parents that do raise brown-headed cowbird chicks, also raise children that are more likely to continue to allow the brown-headed cowbirds tricks. They are not the only species to do this. Cuckoos, cuckoo bees, cuckoo wasps, mountain alcon blue butterflies, black-headed ducks, indigobirds, whydahs, honeyguides, and a few fish also engage in brood parasitism. These other bird brood parasites are less sophisticated, they tend to simply try hide that they added their own egg by removing one egg, camouflaging their own egg in size and color and having their young maturing quickly so they can take advantage of their host-parent’s care. These brood parasites tend to kill all the sibling birds, instead of the meta-tactics of the brown-headed cowbird revenge attacks. That means they are in an evolutionary arms race with their parasite victims, rather than harnessing evolution to their own ends, the way the brown-headed cowbird has. So you see, I mean it figuratively and literally when I say that brown-headed cowbirds are bastards. ---------------- All nest photos are courtesy of Denise Nelson. (none of the brown-headed cowbird images are her work) I am changing my image policy, so the next video will credit other photographers more properly. If your work was used and you are dissatisfied for any reason, please contact me and I'll do my best to work out a solution.