Killdeer arrived back in northern New England last month and have already begun nesting. Being a ground nester, the killdeer has many mammalian predators from which it needs to protect its eggs, including weasels, skunks, opossums and raccoons. Nesting killdeer have a number of responses to predators, which include several different types of distraction displays which draw attention to the bird away from its nest. One of the most common displays is to feign injury by assuming a position which makes the bird appear vulnerable. When a predator approaches, the bird runs away from the nest, crouches with its head low, wings drooping and tail fanned and dragging the ground to display its rufous rump-patch. The predator typically follows, seeing an easy meal, and as soon as it gets too close for the killdeer’s comfort, the killdeer continues to lead it off by alternate flights and sprints.
Coyote tracks led to a hole dug in the snow, with the body of a shrew lying on top of the snow next to the hole. Apparently a coyote had succeeded in catching the prey it had heard, but upon smelling this tiny insectivore, the coyote decided it wasn’t that hungry. In addition to having poisonous saliva that immobilizes small prey, shrews possess two glands on their sides that emit an unpleasant odor, detectable even by human noses. Although this odor did discourage the coyote from eating the shrew, it wasn’t enough to save its life.
Camel crickets are named for their humpback appearance. We don’t often see these wingless insects, for they prefer dark, damp habitats such as under stones and logs, where we don’t often look. However, when there are extreme weather conditions, such as excessive rainfall or the extended periods of hot, dry weather which we have experienced this summer, camel crickets are attracted to damp cellars and crawl spaces, giving us an opportunity to admire their impressive legs. Often mistaken for spiders, camel crickets do have long legs, but only six, not eight, of them. Their two hind legs are obviously longer and stronger than the other four, and enable this cricket to jump three feet high, a skill they use for defense against predators. A local blog reader reports that three nights in a row (camel crickets are nocturnal), due to the force of its jump, a camel cricket tripped a small have-a-heart trap set in their cellar for mice. (Thanks to the Choukas for photo op.)
People used to believe that earwigs crawled into people’s ears while they were sleeping and proceeded to bore into their brains, thereby causing insanity and/or death. Fortunately, this isn’t, and never has been, true. Earwigs feed on leaves, flowers, fruits, mold and insects, but not human brains. Because they are nocturnal, during the day we often find them secreted away in some dark, damp crevice, often on a plant. These flat, elongated insects have a pair of pincers, or cerci, at the end of their abdomen which they use to capture prey, defend themselves and arrange their hind wings, if they have them. (Earwigs that possess wings can, but rarely do, fly.) You can actually determine the sex of an earwig, should you be so inclined, by the shape of its cerci – those of a male (pictured) are unequal in length, strongly curved and larger than the straight cerci of females.
The Viceroy Butterfly closely resembles the Monarch Butterfly, but is smaller, and has a black line that runs across the veins of its back wings, which the Monarch lacks. While Viceroys don’t contain the poisonous cardiac glycosides that Monarchs do, they do contain salicylic acid due to fact that the larvae feed on willows. This acid not only causes the Viceroy to taste bad, but makes whatever eats it sick. So not only do these two butterflies look alike, but they discourage predators in the same way. This is not a coincidence. The fact that they are both toxic if eaten and are preyed upon by some of the same predators has led to their similar appearance. This phenomenon is referred to as Müllerian mimicry, and essentially it means if two insects resemble each other, they both benefit from each other’s defense mechanism — should a predator eat one insect with a certain coloration and find it inedible, it will learn to avoid catching any insects with similar coloration.