Tuesday, May 16, 2017

House-hunting, any cavity will do

Female House Sparrow drawing
It’s spring and the House Sparrows, Passer domesticus, are raising young—you’re right they did it in the fall and they may do it again in the summer.  House Sparrows are exceptionally prolific in their brood production.  They are disliked by many birders partially because of their sheer numbers but also because they threaten other bird populations like the Purple Martin, Scarlet Tanager, and the Bluebird.  Since they nest virtually year-round, they take up the nest spaces for migrating cavity-nesting birds and although they are small, they can be nasty in defending their nests.

Here’s a little bit of House Sparrow history:  First, they are not really sparrows.  They are thought to have originally come from the Mediterranean area and are members of the Passerideae family, an Old World finch family.  They are not native to the U.S. and did not come to the U.S. on their own.  For some that is enough to make them unacceptable, but there is more to the story.  Eight pairs of House Sparrows were taken from England and brought to Brooklyn, New York in the spring of 1851 and released to deal with a caterpillar problem. It didn’t work but they did become permanent residents. Then between 1871 and 1874 additional House Sparrows from Europe were released in Cincinnati, Chicago, and other parts of the U.S.  Small numbers continued to be released in various parts of the country until they were everywhere.  They had no natural predator and they were very successful breeders, so their numbers kept increasing. Many think they have threatened the viability of other birds because of their fecundity.

But…on a cold winter day, it is enjoyable to watch House Sparrows on city streets and in parks.  And in the spring, we can watch as they make nests in just about every cavity they can find—from the crooks of the arms of statues, the eaves of apartment buildings, the tops of traffic signals, and just about every tree you can think of.  House Sparrows partner up in the winter and generally are monogamous throughout their lives although it is true that if a partner dies, they soon find another to take his or her place.  They are breeding machines.  After nest building, the male defends the nest so that the female can begin laying 4-6 eggs.  These eggs hatch in about 12 days and leave the nest in about two more weeks.  Both male and female feed the fledglings, but once they are out of the nest, the male takes over the feeding, and the female prepares for her next nesting cycle.  The House Sparrow I have drawn is a female; she has yellower beak than the dark one of the male and soft buff, brown, and cream coloring

House Sparrows are omnivorous; they eat just about everything from seeds, berries, insects, spiders, discarded hamburgers, and the photographer for our book, Field Guide to the Neighborhood Birds of New York City,  Beth Bergman even found one chomping on an old cigarette butt. This is also a factor in their success in the U.S.  Fast food is as tasty to them as a fine mosquito.  They can live just about anywhere, eat just about anything, and reproduce year-round.  They bathe in mud and have little or no fear of humans.  Sounds like they are perfect for the New York City life.   

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