Out of genuine interest rather than any particular career planing, I spent this past summer working an internship at Avian Wildlife Center that rehabilitates and releases injured wild birds, anything from hummingbirds to herons. Most of the birds we dealt with were brought to us after unfortunate interactions with humans in some way – nest disrupted, hit by car, poisoned by pollution, etc. At the center, birds receive care until they can be released back into the wild.
Before release they are also tested for parasites, ability to self-feed, and feather condition. During their time at the center people interact with them as little as possible so they don’t learn to associate humans with food and approach them after being released.
It’s a great and rewarding job, if you aren’t expecting high pay, flexible hours, or a stress-free work environment. It’s also pretty interesting, and I could (and did) leave work every day with multiple bird stories to share.
One particularly interesting case we had was a lady who brought in a fallen sparrow nest, with three baby birds. She commented that she was surprised one of the babies was twice the size of the other two. This is because one wasn’t a sparrow at all, but a cowbird. They are incredibly interesting birds, particularly in how they raise their young – they don’t. Instead, they are nest parasites: the mother cowbird flies around laying eggs in other birds nests to be raised by an unsuspecting parent bird, in this case a sparrow.
The lady, who before this information had been impressed by his advanced growth, was suddenly appalled at the poor little cowbird in her sparrow nest. She then asked if we would euthanize the “parasite” since it disrupted the life cycles of the other birds. Of course that is not the case, and we explained that we would take care of it just the same – the center takes any injured wild bird, irregardless of how many individuals of that species they might already have because it makes no attempts to influence natural population ratios.
She wasn’t convinced why it should be saved, which was a common sentiment among several of the rescuers of cowbirds we spoke to over the summer.
Perhaps the term “parasite” gives them a bad reputation, but cowbirds are truly fascinating. Where most other species would imprint on whatever they first see – imagine the classic example of a baby duckling who imprints on a human when it hatches and spends its day following people instead of fellow ducks. Cowbirds, however, are smart enough to know what they are without having to see another cowbird during their whole infancy. This is because they recognize their own coloration and use that information to find mates in the future.
Generally, to the public we simply try to explain that it is the bird’s natural behavior which should not be tampered with. Cowbirds are not an invasive species and are completely meant to coexist with other birds in their natural habitat, which ranges all across North America from southern Canada to southern Mexico.
They can’t thrive without this method of reproduction, which arose naturally through co-evolution with competing bird species. It is simply how they live and reproduce, and the individual should not be blamed for its innate biological behavior, any more than a hawk should be blamed when it kills a dove for its dinner.
This isn’t to say that cowbirds don’t harm other birds – I am sure that unknowingly raising a baby cowbird takes its toll on a sparrow mother, who will be half the size of her baby before it leaves the nest. But they don’t outright kill their hosts (a good parasite doesn’t kill its host, or it loses its livelihood), and the parents with whom the cowbird tries to leave her eggs are not completely defenseless in the matter, as they sometimes detect and eject foreign eggs.
Still, there is so much love (and funding to care for) birds of prey, who must kill to consume at least 20% of their body weight a day to sustain themselves. People marvel over the beauty of an eagle soaring in the sky while nest parasites, such as cowbirds, cuckoos and several other species, are met with animosity – even though they are usually not responsible for the deaths of any other birds and are equally fascinating creatures.
- (An exception is if a cowbird egg/baby is discovered and tossed from the nest by the duped parent. A response, nicknamed the “Mafia Behavior”, occurs where the mother cowbird will return to the nest and destroy the other eggs, in hopes of forcing the victim to create a new nest and lay a new brood, also giving her another chance to lay new eggs).
Cowbirds are somewhat infamous for contributing to the near extinction of the Kirtland’s warbler and there were even several mass attempts to remove cowbird eggs from warbler nests, although later it was found there were several other factors leading to their decline besides cowbirds, mostly from human damages to the ecosystem. And studies have even shown that when humans try to remove cowbirds, we end up helping them – removing birds from an area signals less competition, so they are able to reproduce more in that area and end up parasitizing even more nests than they would normally would have.
As with any animal that makes its way through life by competing with others, there are winners and losers. As a rehabilitator, helping one means eventually harming another, as the circle of life continues in the wild and someone must be preyed or parasitized upon. That doesn’t mean efforts to protect the environment are any less meaningful and perhaps the best thing we can do is try to fix the damages done by humans and restore the balance that existed before human activity began to cause serious disruptions.
After all, these species got along just fine before humans showed up to observe, monitor, and “fix” nature.