North American Birds

VOLUME 69 NO2 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/705084

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T H E C H A N G I N G S E A S O N S : C A R B O N C O P Y N O R T H A M E R I C A N B I R D S 206 looking for birds and where. But it's clear that every element of birding has under- gone, and continues to undergo, a radical increase: numbers of adherents and hours in the field, locations covered, quality of optics and cameras, overall competence of observ- sided Warbler north of Florida in December, but we now see photographs almost instan- taneously, and we're able to verify that such delicate birds can hang on well into winter, so long as they have shelter and food. Armed with good information, rapidly distributed, with good documentation, we are more dis- cerning in the spots we check, far more so- phisticated in the foods we offer in the back- yard, and better prepared to identify these winter rarities accurately. As Dave DeSante (1976) wrote in the winter column forty years ago: "Range expansions, extra-limital records, and vagrant occurrences continue to be noted in increasing numbers and with increasing frequencies. This fact may have profound evolutionary significance if there are actually more birds involved in this pro- cess and not simply more birds seen. Not only are the numbers of birders and the time they spend in the field greatly increasing, but more of them are looking for unusual birds and are also becoming more knowledgeable of locations where unusual birds are likely ers, and usable documentation of winter rarities. Even without the hyperconnect- edness we take for granted, every indica- tion is that our "coverage" has increased by multiple orders of magnitude in the past 10-20 years. So are we correct in our assumption that warmer (overall) winters are responsible for the increase in reports of winter warblers, tanagers, and allies? Or shouldn't we instead as- sume that the number of records should correlate to the hours in the field (and quality of these hours), along with the hours spent watching feeding stations? If so, then one could argue that little has changed, that we're just better at finding the birds that are often either left behind (because of ailment, injury) or that seem to be reverse migrants bent on flying north- ward in fall instead of southward. And isn't the advent of digital cameras another con- sideration: even into recent times, skeptics rightly scoffed at reports of "non-hardy" spe- cies like Swainson's Thrush and Chestnut- Figure 13. An exceptional winter find was the Sanderling 19 December 2014 on the salt flats of the Salt Plains National Wildlife Refuge, Alfalfa County, Oklahoma. Photograph by Steve Metz. Figure 14. This adult Common Loon made a real attempt at overwintering on a short stretch of open water along the Yukon River in Whitehorse at least from 26 (here 28) December 2014 through 31 January 2015, after which date its fate was uncertain. Photograph by Cameron Eckert.

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