Blane Klemek: Birds pipe down this time of year, but some are still singing
Last week, I heard singing marsh wrens, sedge wrens, mourning doves, and black-capped chickadees.
Though migrant songbirds are still among us, either showing up at our bird feeding stations or observed in fields and forests everywhere, the paradox of songbird abundance at the peak of the summer is that the “song” part of their collective namesake has begun to die down. Put another way, it’s less musical in the great outdoors.
Nesting season is winding down for many migrant birds. While some are busy feeding second broods at this time of the season, with some birds even incubating third clutches of eggs or feeding their third families, courting and singing is almost non-existent now.
Save for a few species of birds such as red-eyed vireos and American goldfinches that are still singing their hearts out, not many birds are necessarily singing.
The songbird vocalizations that we hear this time of year are mostly call-notes, distress vocalizations, warning or surprise calls, etc., but not all. As mentioned, some species are still singing. Last week while on a field trip to Lac qui Parle (LQP) Wildlife Management Area, LQP State Park, and other areas in the Minnesota River Valley, I heard singing marsh wrens, sedge wrens, mourning doves, and black-capped chickadees.
- BIRD CALLS: LIsten to the sedge wren , the marsh wren , the mourning dove , and the black-capped chickadee , courtesy of the Cornell Lab’s All About Birds species guide
As musical as bird songs are, they are not, as some people would like to imagine, produced for the birds’ individual pleasure — or ours. While it is true that not all songs and calls of birds are linked to territorial and mating-related activities, many vocalizations are, especially during the spring breeding season.
Male American robins, Baltimore orioles, red-winged blackbirds, house wrens, and countless other birds throughout our region sing boisterously in defense of their territories every spring and early summer.
For example, male red-eyed vireos, sometimes called preacher birds because of their incessant singing, sing all day long from woodland treetops. As pleasant as it sounds to our ears, to the ears of other male vireos the song is notice that the territory is occupied.
The same is true about eastern and western meadowlarks singing from a fencepost in the open country, or the rose-breasted grosbeak singing from the treetops or the gray catbird singing from the thickets. And the list goes on.
Increased singing activity in many male birds is linked to elevated testosterone levels in their bloodstream. The length of daylight, or photoperiod as it’s called, triggers this physiological change.
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Also affected are specific territorial behaviors. But interestingly, not all full-chorus singing is necessarily exclusive to springtime. A few birds sing in the fall too. Male European starlings and house sparrows experience higher testosterone levels in autumn during their fall molts and actually begin claiming nesting sites. Other birds have also been observed singing in the fall, including song sparrows, white-crowned sparrows, and American robins.
Typically, however, singing is conducted in the spring. And all that singing leads to eventual pair bonding, mating, nest building, and raising offspring. Right now in wetlands, fields, forests, and backyards throughout Minnesota and elsewhere, most wild birds are actively caring for young or finishing their parental duties.
As needy nestlings gain their independence and confidence, they’ll soon join others in large flocks as their focus turns to preparing themselves for the annual migration southward by eating plenty of fat-building, nutritious foods.
An interesting fact about birdsong is that the same species of bird may have different dialects depending on where they come from. This shouldn’t come as a surprise, because the same is true for humankind. How many times have we commented at how different someone sounds from, say, the Deep South as compared to those of us here in Minnesota?
As mentioned earlier, during my trip to southern Minnesota last week, I heard wild birds singing. One species, the black-capped chickadee, a familiar and widespread species, were surprisingly singing their fee-bee song (this song is generally sung in the mid-winter and early spring). What was fascinating, however, was that these southern chickadees sounded slightly different from their conspecifics breeding and nesting where I live near Itasca State Park.
Birdsong is pure delight, no matter the species that’s singing. And though their songs bless our ears with listening pleasure for only a brief period of time each year, rest assured that we still get to observe the comings and goings of migrant wild songbirds for a little while longer before they migrate once again, as we get out and enjoy the great outdoors.