Swallows have mastered the art of hunting for bugs while flying, and cliff swallows are no exception to this. Their quick maneuvers, small build, and agility make them incredible insect hunters. They mostly feed on swarms of insects, and they even have a special call to let other swallows know when there is a really good food source nearby.
Cliff swallows actually have the opposite problem than most birds — they have thrived in recent years. One of the reasons for this is that there are a lot more structures that support their nesting habits. For example, the first time I saw cliff swallows, they were nesting underneath a bridge. Infrastructure such as tall bridges and overpasses gives them more habitat to nest in, which has helped keep their populations stable or rising.
They nest in huge colonies with potentially thousands of nests at one sight; the largest sight ever found was in Nebraska with up to 3700 nests. They also exhibit a lot of group behavior, such as migrating together. They also preen each other often. Despite this fun group dynamic, there is still bitter competition for good nests, and pairs have to defend the nest they build (or stole) from other cliff swallows.
Their nests are also built in an interesting way. Because they normally would live on a cliffside, they would build their nests using mud that they gather on their bills. Sometimes this mud can be from sources that are miles away! They shape their nests using a shaking motion, and building a nest can require over a thousand pelts of mud! Male cliff swallows will start a nest to attract a female cliff swallow, and then they stay a pair to raise the young (even though both swallows are not monogamous with each other).
Because many cliff swallows live on bridges, they are often the victims of car strikes and end up as road kill. As the number of cars are increasing on the road, logically you would expect that the amount of cliff swallows killed by cars would also increase. But that hasn’t been the case. Cliff swallows are actually less likely to be killed by a car strike. But why? Interestingly, scientists have discovered that cliff swallows wings have actually been getting shorter. They theorize that it is because the shorter wings help the swallows to make even quicker maneuvers which leads to higher rates of survival and therefore reproduction.
I find it so intriguing to find such exponential rates of evolution due to humans, such as the moths during the industrial revolution. Our behavior has forever impacted a creature down to its DNA, and that is both awesome and completely terrifying. Long studies like the one performed to discover this are so essential because there could be other cases like this that we aren’t seeing since we aren’t looking for it. Next time you get in your vehicle, remember that it has forever changed the DNA of a species of bird.
As I’ve probably commented before on your blog, I know almost nothing about birds, except some are cute and others terrify me. The cliff swallows are just cute, thankfully!! I love how you not only provide a basic background on the bird, its diet, where it lives, etc., but also how climate change and threats to their species have impacted them! Birds are often keystone species, and without them, entire ecosystems would crumble. Yay birdies! Great post!