Let’s have a chat

By BILL CHAISSON
Of A Feather
As the nesting season advances, I have considered writing about dummy nests, but that can wait till later this month. Right now, I feel like reflecting on my “experiment” of taking the same 10-minute stroll each morning with Merlin recording. I try to get out there at 6 a.m., but this morning it was 6:30. In any case, the sun has been rising earlier each day. So, as far as the birds are concerned, I’ve been getting up later and later. That is likely one reason the observed diversity has tapered somewhat through the season: I am now missing the “dawn chorus” by an hour (sunrise was at 5:07 this morning).

When I began this daily ritual in late April, I was greeted by blue-headed vireos. Now they are gone and replaced by the red-eyed vireo. In early May I heard both wood thrush and hermit thrush singing, but now I hear neither, only the downward chirp of the veery. Many warblers have come and gone, leaving the yellowthroat, chestnut-sided (a later arrival), black-and-white and pine warblers as the only consistent presences.

Some species appear only occasionally, as if we are at the edge of their territories. Our neighborhood purple finch delights me about once a week. Other ephemerals include a black-throated blue warbler, ovenbird, a cowbird, a rose-breasted grosbeak, a Baltimore oriole and several species of woodpecker. A few are more vocal later in the day: indigo bunting and song sparrow.

A visit from my brother, who lives in Maryland, made me think of a bird I am entirely unlikely to see or hear at any time of the day, but has always intrigued me: the yellow-breasted chat. This odd bird ranges north only to central Pennsylvania in the East, but in the Midwest finds its way up into southern Saskatchewan and Alberta and is found west to California coast (but is absent from the Oregon and Washington coasts). It visits New Hampshire only rarely, and then as a rather lost migrant in the fall and even more rarely in the spring.

Thomas Mayo Brewer, writing in 1878, reported that 10 years earlier C.A. Hawes found a nest with four eggs in North Conway, New Hampshire, of all places (The Birds of New Hampshire). This report was not taken seriously, and the earliest accepted record is a female found dead in West Concord in September 1909. The only known reliable report of breeding is from Hooksett before 1953 (reported by Arthur Cleveland Bent with no specific date). There have been scattered sightings since 1950, most of them in the fall and most of them along the seacoast, but one as far north as Berlin.

The chat intrigues me because of its uncertain systematic position. In bird guides it is often placed at the end of the warblers, the way the brown creeper gets tacked on to the nuthatches. Molecular evidence, usually so good at solving these puzzles, reveals nothing definitive as yet. Studies have placed the chat variously nearer to the warblers, the blackbirds and orioles, and even the sparrows and buntings. Anatomical evidence points to a relationship with the tanagers and pushes them further from the warblers. At present it is placed in its own family, the Icteriidae, a name like that of the blackbirds, and its own genus Icteria, in which the species virens sits by itself.

At seven and a half inches, the yellow-breasted chat is a good two inches longer than most warblers with a bill as heavy as a tanager’s. Its back is an even olive green, the throat and chest are bright yellow and the belly is white. Its head is ornamented with bright white spectacles (like those of a blue-headed vireo) with black lores (the area between the beak and eye). Its tail is long and rounded, and it flops around when it flies, which it is seen to do only rarely. It prefers to forage for insects and spiders in dense thickets, gleaning them from foliage.

The chat’s display flight is an exception to its usual furtive behavior. Males deploy this behavior for females, for male intruders into their territory, and even in response to human intruders. Consequently, researchers are uncertain as to its purpose, other than to announce the bird’s presence and aroused state. Birdsoftheworld.org describes thus: “Display flights usually begin from a high perch from which the male (while singing) descends, often in jerky bounces, with exaggerated wing beats; drooping, often spread, tail; and, sometimes, dangling legs … Often at the end of the flight, a thumping sound, presumably made by the wings, can be heard.”

The social structure of the chat community seems complex. Early observers thought it might be colonial, but more recent observations suggest that males are simply frequent intruders on each other’s territories. Indeed, one DNA study showed that 38% of nestlings were not sired by the male in whose territory they were born. The chat maintains a polite hypocrisy in daily life, being “socially monogamous, but genetically polygynous.”

While generally common, the numbers of the yellow-breasted chat (like those of many songbirds) have declined over the years. It seems to have retreated from the northeastern edge of its range and is no longer seen as frequently in Connecticut, New Jersey, or New York. This is the opposite of what hypotheses about warming related to climate change would predict.

Instead the decline of the chat appears related to land-use practices. It requires dense, early successional growth, the habitat that grows up following logging. As more forest is allowed to succeed to a closed canopy and remain that way, chat habitat disappears. In a study that looked at chat abundance after various types of selective cut versus clear-cutting, the chats were most common after lots had been clear-cut.

I saw no studies of it, but I wonder if over-population by deer, which denude the understory in suburban areas, might also have an impact.

Bill Chaisson has been a birdwatcher for over 50 years. He lives and works in Wilmot.