Nature Notes: As the Snowbirds Return

Most bats are nocturnal and have well-developed, built-in sonar systems for locating flying insects in the dark

    Victoria and Nicholas Bustamante were walking Shadmoor Park on the ocean in Montauk on Saturday afternoon when a bat flew overhead. Nicholas threw up some pebbles and the bat made a pass at them. It looked red, Vicki said, and was a little bigger than a little brown bat, the most common bat on the East End during the summertime.

    Most bats are nocturnal and have well-developed, built-in sonar systems for locating flying insects in the dark. They don’t see so good in day or night. The bat that Vicki and Nick saw was an exception to the rule. The red bat is one of the few bats that is not nocturnal and is able to see to feed quite well during the daytime.

    Red bats tend to be solitary, unlike the little brown bats that roost, nest, and fly in groups. The brown bat population is being depleted by white mouth, a fungal mouth disease. In the winter brown bats migrate from subfreezing temperatures in the north to caves farther south where the temperature rarely goes below freezing. They spend their days in semi-hibernation clustered together on rocky niches, a good way to wait for spring, but not good if one or more have the disease. It easily spreads under those conditions.

    Bats’ echolocation works during the day or night, so why not feed both at night and in the day? Because insect hawking birds — the flycatchers, swallows, swifts — and others that are adept at removing insects from the air column and by sight evolved those abilities prior to bats. Bats, with the exception of a few, would not be able to compete. So the bats that fly during the day and are solitary are an exception to the general rule and manage to eke out a living feeding like flying birds.

    Having the night air all to themselves, bats evolved to fill several different niches, just as the birds did before them. There are fruit-eating bats, fish-eating bats, blood-sucking bats, and those that feed on other plant and animal stuffs. Many bats will take mosquitoes now and then. The vampire bat has evolved further; it competes with the mosquito for mammalian blood. Watch out for global warming, as it will bring us lots of newcomers from the south, new disease-carrying mosquitoes, as well as blood-sucking bats.

    Many North American bat species migrate north in the spring, south in the fall, as do many species of birds and fish, as well as a few butterflies and dragonflies. Bats usually arrive a month or so later than the early birds, which are already upon us. When the Major League baseball players go south for spring training, several bird species arrive in the north from the south to begin the next breeding season.

    On Feb. 4, a flock of about 30 male red-winged blackbirds showed up at the Bustamante feeders in Montauk east of Lake Montauk. On the same day, a similar-size flock flew into my neighbors’ yard to feed. In both cases, all of them were males. The sexes are segregated in many early migrants, including robins and purple grackles. A few grackle males were mixed in with the red-wings in both situations. It’s that same old argument that created separate boys and girls schools and colleges in America. Keep the sexes separate, fewer premature births. It works for birds. Does it work for humans, too? The jury is still out.

    We non-snowbirds have suffered enough already, but relief is in sight. The great migration has begun. Spring is just around the corner. The permanent resident birds — the titmice, cardinals, and chickadees — have already started singing their territorial songs. The white-throated sparrows that winter here and fly farther north to breed are looking fine of feather and singing their very mellifluous “Old Sam Peabody” song. If you stick your head out the window on a warmish sunny day you may be able to hear it. Unfortunately, the song is well above old Larry Penny’s hearing range. I can only observe the sparrow uttering it. But as sparrows have no lips, I can’t figure out what he’s saying.

    Larry Penny can be reached via email at