VOLANT, Pa – Our class’s most recent adventure in the Tweetspeak cluster took us to the Grassland Strips, aka the Black Swamp. It is a location that provides a multitude of habitats for bird species of all kind. It was also my first time seeing many new species there such as Killdeer, American Coots, and the Green-winged Teal. The most notable sighting for me though was that of the Sandhill Cranes. I observed them in an open field foraging for food.
Cranes are one of the largest types of birds. According to allaboutbirds.org, Sandhill Cranes generally range from about 47.2 inches in length, between 119 and 172.8 oz. in weight, and have a wingspan of about 78.7 in long. To put things into perspective, they are larger than an eagle but smaller than an ostrich. But why are these birds so big? And what can possibly hunt a bird this size? My curiosity took me back to a lesson I learned about in the biology portion of the cluster concerning natural selection.
Natural selection, is the fundamental principle for how species evolve overtime. It is the process by which individuals belonging to a species have traits that help them better adapt to the environment enabling their survival and allowing them to produce more offspring. Traits well-suited to the environment are known as adaptations. They form as a result of selective pressures presented by th environment in which a species lives.
According to audubon.org, Sandhill Cranes live in a variety of different habitats including prairies, fields, marshes, and tundra. Their habitat largely depends on what region a population lives in. This ultimately causes their environmental pressures to vary. Sandhill Cranes are scattered throughout various parts of North America including places such as the Artic, northern U.S., and central Canada.
Their location largely determines what environmental pressures they are exposed to. Because they are a wetland species, their adaptions are specialized for watery environments. Let’s look at the source of their height for example, their long legs. Learner.org suggests that the reason for their legs being so long is to aid their ability to stand above water without getting their feathers wet. A bird’s feathers are one of its sources of warmth. They provide insulation when a bird is exposed to cold temperatures. If they were to get wet, the bird is subject to loss of heat which can lead to hypothermia.
As for what hunts the Sandhill Crane, the list is just as intriguing. Predators of this species include coyotes, bobcats, and eagles. It only makes sense that a large bird would have decent sized predators. Because Sandhill Cranes are located in different types of habitats, it also makes sense that their predators are just as diverse as well.