The summer is rapidly drawing to a close. The chorus of birds that I could hear from my bed at 5:00 a.m. in June has dwindled to almost nothing and mornings are silent. We have not been entirely deserted, however. The gray catbird which nested in our yard this summer still skulks through the understory of our woods, uttering commentary in a recognizable catbird voice.
Catbirds can be found in every county in Minnesota, although T.S. Roberts in 1932 observed that they had only recently been seen on the Mesabi Iron Range. They are drawn to forest edges, streamside thickets, old fields and fence rows. They are common backyard birds, nesting in the dense tangles of shrubs, such as bridal wreath and snowball.
Their nest is an open cup, placed on sturdy horizontal branches, woven from twigs, straw, bark and mud. A nest in our yard included a tatter of plastic sheeting. The nest is situated about four feet from the ground in a tangle, so that the birds sneak on and off the nest, moving under the radar. They lay from one to six deep turquoise eggs, which are then incubated 12-15 days. Hatchlings remain in the nest 10-11 days more before fledging. The Smithsonian Migratory Bird Center research findings suggest that nearly half of all catbird fledglings are killed by roaming house cats.
Catbirds are berry eaters. The service berry bushes in our yard attract adults and young. On summer evenings, I hear them rustling through the leaves in search of elusive berries. But grapes, elderberries, blueberries and raspberries are all appreciated. Every source I consulted mentioned that catbird voracity for berries can make them garden pests, vying with humans for fruit. The birds also consume large amounts of insect grubs like cutworms, or little green caterpillars. These form the bulk of food for young birds, enabling them to put on weight with the high-protein fare.
The birds also consume large amounts of insect grubs like cutworms, or little green caterpillars. These form the bulk of food for young birds, enabling them to put on weight with the high-protein fare.
Catbirds are mimics, in the same family, Mimidae, as thrashers and mockingbirds. The catbirds in our yard this summer sounded like robins, since robins singing a territorial song were their nearest neighbors. The name, of course, comes from a startlingly realistic “mew” like a feline. Male birds often choose a prominent, high perch to sing from, hence the phrase, “sitting in the catbird’s seat.” Catbirds also sing at night, particularly at full moon, one of the few birds to do so.
The Smithsonian Migratory Bird Center is conducting research on catbird migration. Birds are captured in nets and fitted with tiny, lightweight GPS tags, which are held in place by miniscule lightweight harnesses of elastic thread. The birds have to be recaptured to recover the data., so many of these GPS tags are never recovered. With over a hundred birds tagged, the Smithsonian is collecting interesting data. It found that catbirds in the Washington D.C. area overwintered in the Everglades and at a wildlife refuge along the Gulf Coast. It also learned that once the birds arrive on their overwintering grounds, they stay put and move around very little. Apparently, if the winter grounds has sufficient food, there is no need to wander.
Roberts recorded the time of fall departure for Minnesota birds to be sometime in late September. Until then, I’ll be listening for the catbird voice in our scrubby woods, not singing to defend a territory, but companionable, nonetheless.
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