Cowbirds are among the most common bird species around farms and backyards. While at first glance they look like a normal blackbird, there are many things about them that actually make them incredibly unique. Here are five things you may not know about cowbirds.
1. They’re Parasites
This is something that many people likely already know, but it’s important to go over to lay the foundation for other wild facts about cowbirds. Cowbirds are brood parasites, meaning they lay their eggs in the nests of other birds, leaving the chicks to be raised by a completely different species. To ensure their survival, their chicks grow faster than the chicks of other birds, meaning they will outcompete the parents’ own hatchlings. In the United States, Brown-headed cowbirds have been documented doing this to the nests of over 200 different bird species, and do present a problem for many of them. It’s believed that cowbirds adopted this strategy to follow herds of large animals moving across the plains and open spaces in western North America. Moving with large animals meant they couldn’t stay in one palace to make a nest and raise young so they found a creative solution. Some people debate this, as the reason for their nesting strategy but either way it resulted in this unique behavior. Over the years, humans made North America more suitable for cowbirds, clearing land and creating backyard feeding stations, allowing them to hang out in one place and parasitise birds all across the continent.
2. There Is More Than One Species
The cowbird species that most people are familiar with is the Brown-headed Cowbird. They are common throughout most of the United States and show up often around back yards, parks, and gardens. There are actually two other cowbird species that live in the United States and a few more in other countries as well. The Shiny Cowbird lives throughout South America and has a little bit of a range in the United States, primarily in southern Florida. The Bronzed Cowbird is probably the type of cowbird seen most in the US aside from the Brown headed Cowbird. They can be found in many of the southern states with South Texas being one of the most notable places to find them. Something cool about them is that they have a distinctive red eye and males have feathers on their neck that they can puff up, giving them something of a hooded appearance. Another interesting thing about them is that they’ve expanded their range northward and now overlap in range with other cowbird species. In fact, both Bronzed and Brown headed cowbird eggs have been found in the same nest. It will be interesting to see how the North American cowbird species exist together going forward.
3. They Don’t Learn Behaviors
Most animals, including many birds, learn their behaviors from their parents. When birds hatch, they imprint on their parents, learning what species they are, and developing a sense of identity. For this reason when raising certain species in captivity, puppets or sometimes full costumes are used during feedings to make sure young birds don’t imprint on humans. If they do imprint on humans then they can’t be released into the wild so imprinting is a pretty serious thing. This is the case for Whoopings cranes as well as a whole host of other birds. With cowbirds however, this isn’t the case at all. Since the eggs are deposited in another nest and raised by a completely different species, cowbirds learn almost nothing from their what we’ll call “unintentionally adoptive parents”. When they become adults, they are equipped with all of the skills a cowbird needs including the cowbird song, mating display, and parasitic nesting that they’re known for. All of this behavior is inherently woven into the bird without them ever learning from parents or other cowbirds/ This is absolutely remarkable and adds an interesting wrinkle into the nature vs nurture debate.
4. Females Are Incredibly Drab
It’s quite common for female birds to be significantly less colorful than the males. The reason for this has to do with the fact that it’s better for them to stay hidden while on their nests. Cowbirds take this a step further with females being possibly the most drab and nondescript of all bird species. This is because they need to sneak into the nests of other birds undetected. Moving like a ninja or a secret agent, female cowbirds are able to infiltrate a nest while the parents aren’t looking and add their own eggs into the clutch. If they were more brightly colored, this would be a much more difficult feat. In fact, even humans have trouble spotting female cowbirds sometimes, especially if they’re hanging out in shrubs and brush. You will get a look at them at bird feeders though where you may at first wonder what exactly you’re looking at.
5. Illegal to Harm
Cowbirds seem like they would be an invasive and nonnative species due to the way they gather around feeders in large numbers and cause problems for other birds. However, they are actually a native migratory bird which means they are protected from being harassed or harmed by the migratory bird treaty act. So to anyone out there commenting about how you want to shoot them when they’re at your bird feeder, that is in fact actually illegal. However, there are places where cowbirds have to be managed such as kirtlands warbler habitat where cowbirds invading nests would be detrimental to the health of the species. The biggest take away here is that even though cowbirds, especially brown headed cowbirds are problematic in some places, since they are native to North America, they are still a protected species.
Cowbirds are certainly unique birds that are now common around homes and gardens but there is still more to them than meets the eye.