North American Birds

VOLUME 69 NO3 2016

A Quarterly Journal of Ornithological Record Published by the American Birding Association. The mission of the journal is to provide a complete overview of the changing panorama of our continent’s birdlife.

Issue link: http://nab.aba.org/i/778845

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Figure 10. A pair of Tufted Flycatchers discovered in upper Ramsey Canyon 22 May 2015 (here) represented the first nesting attempt for Arizona and the United States. Photograph by Charles Melton. Figure 11. British Columbia's fourth Crested Caracara was photographed near Nanaimo on Vancouver Island 20 July 2015. Photograph by Graham Ford. N O R T H A M E R I C A N B I R D S 348 T H E C H A N G I N G S E A S O N S : R E T R O S P E C T records—from Alaska to Newfoundland— one ima-gines both could be involved. Even though the range has expanded in the con- tinent's center (and along the Gulf coast), decades of "overshoots" in the East, for instance, have not produced nesting birds north of North Carolina, though certainly some spring birds do croon for days on end, apparently in search of a mate. Time will tell if this species makes greater gains geographically. Formerly a species of the southern-tier U.S. states and southern portions of adja- cent states (north to southern Nevada, Utah, Colorado, Kansas), Great-tailed Grackle has been expanding northward for several de- cades now. A highly social species that nests in colonies and roosts communally, Great- tailed has shown a somewhat patchy ex- pansion, absent over large areas that seem suitable and found far from typical range as singles or small groups that persist for long periods. This pattern is familiar from other expanding species that are social, such as Fish Crow in the East and Midwest, whose expansion has also partly followed river valleys. Another milestone for Great- tailed Grackle was notched with Alberta's first record this year (Figure 6), and with new gains in Iowa and Minnesota, and the species appears to be established in Jackson County and maybe Harney County, Oregon as of 2015. How much of the range expan- sion of this species is owing to landscape modification versus warming climate is un- known, but it is interesting that the other extant "Cassidix" grackle, Boat-tailed, has expanded northward during the same peri- flies, swifts) are available, range consolida- tion seems likely. One wonders whether the northward movement of White-tailed Kite into the Pacific Northwest during the same period was a response to warming climate or perhaps to changes in agriculture and other landscape alterations. Both kites are highly mobile and presumably able to ex- ploit local, ephemeral abundances of prey, but of course, climate changes are factors in prey distributions as well. A prized vagrant over much of the con- tinent two decades ago, White- winged Dove now borders on be- ing ho-hum; we scarcely bat an eyelid now when one turns up at Wrangell, Alaska in winter or on Akimiski Island, Nunavut in spring (Figure 5). And the breeding range of the species has certainly moved northward, perhaps 700 kilometers over the past century (Schwertner et al. 2002), but most of the truly wild northerly records have come in the past 20 years. We don't know whether the source of vagrants is the (introduced?) Florida popula- tion or the western/Gulf popula- tion, but given the span of vagrant Ibises and stilts have become expected visitors to northern regions in a relatively short period of time, and in some cases have established northerly breeding outposts in places where seldom or never before documented. The birding community has become aware of their arrival because hun- dreds or thousands of individual birds have been documented. In some cases, just a few individual birds can have similar impact on our awareness of southern species in north- ward expansion. Almost a poster child for species expanding during global warming, Mississippi Kites have gone from barely breeding in southern Virginia in 1995 to now nesting in New York, New Hampshire, and even at Winnipeg, Manitoba! These nest events are still very much isolated, though the habitat in which they have occurred (mostly suburban areas with large shade trees) is not scarce. Mississippi Kites were seen irregularly as spring "overshoots" be- ginning mostly in the 1980s. The scattered northern nestings still hold a rather sacred status, and it is impossible to know whether these betoken arrival of more nesters in the Northeast and Prairie Provinces. But if the habitat is not at a premium, and satisfac- tory populations of prey (cicadas, dragon-

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