North American Birds

VOLUME 70 NO3-NO4 2019

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/1115839

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The first year that southern waders wandered to the north of their range birders were awed and enraptured. As this phenomenon has repeated in following years birders have been left wondering if this will be a yearly occurrence or whether all will return to "normal" given a little more time. Photo by © Mike Hudson. 251 V O L U M E 7 0 ( 2 0 1 9 ) • N U M B E R S 3 / 4 The Changing Seasons: Northward March of... Almost Everything The Changing Seasons: Northward March of... Almost Everything MIKE HUDSON • 928 S CONKLING STREET • BALTIMORE, MARYLAND 21224 • (MHUDSON@ABA.ORG) S o, let us talk about what happened over the spring and summer of 2016. In the pages of the regional reports that follow, you'll read about all the trends that we have come to be fa - miliar with: Late lingering waterfowl were wide- spread across much of the continent; there was a wave of early passerine migrants; and many species across many taxonomic groups overshot and ended up well north of typical breeding ar - eas. These are all patterns that we, as birders, have become used to encountering. Perhaps we have become so used to them that we are some - what desensitized! Someone recently said to me, "There are only so many times you can write an essay about how spring arrivals are getting ear - lier, breeding ranges are expanding north." I certainly get that. This is not new territory for this column. Versions of this essay have been written before—by me, no less, and of course by my predecessors. Last issue, my column focused around overwintering insectivores and my first "Happening NOW" blog post from back in 2017 was about the increasing vagrancy in several southern species of wading birds. On the one hand, this is not an exciting and innovative topic and so it might seem rote and unimaginative for me to write about it. But I think that we need to look at this particular topic in a slightly dif - ferent way. As I was reading the regional reports, what began to stand out to me was… nothing in particular. Many species were mentioned re - peatedly—Blue Grosbeak for example, set new northerly records in multiple jurisdictions, as did Orchard Oriole and Summer Tanager. Black- bellied Whistling-Ducks popped up in regional reports from the Gulf Coast to the Midwest. Little Blue Herons and Snowy Egrets seemed to have busy years, spreading across the interior of the continent as well as north up the East Coast. There was no one species, no one trend that was preeminent and domineering. And consider, that these species I mentioned above are just some of those reported on; think, for a moment, about those species not men - tioned. In my home state of Maryland, the steady westward march of Carolina Chickadees was on - going at this time and has continued since then, such that the known hybrid zone has shifted noticeably, cutting deeper and deeper into ter - ritory once inhabited solely by Black-capped Chickadees. I bet in your own states and prov - inces and counties there are similar stories that are well-known and documented, but that don't get reported on regularly. So what doesn't figure in the recitation of species above? In literal terms, there are plenty of species that don't get a mention here. But in practice, we have the bases pretty well-covered. If you go down the list and consider regional re - ports from across the continent, most taxonomic groups had at least one or two species that es - tablished new high counts in interesting places, bred at some new northerly latitude, or estab - lished a new northern record. And I really mean that. As I was sitting and writing this, I kept thinking I'd come up with a family that didn't fit, but upon referencing the reports, I was able to find a mention or two (try it yourself with such groups as raptors, procellarids, etc). One thing that may mask this on a season-to- season basis is the way that other factors influ - ence many relatively small changes. For instance, some of the new northerly records I mentioned were only a county north of the prior record. On a scale like that, many things could be respon - sible for a new record. However, over the course of a whole year and, especially, over multiple years, these changes may begin to become ap - parent. The first year that southern waders, like Roseate Spoonbills and Wood Storks, began ap - pearing in far flung locations in large numbers it was widely suspected that fluctuating water levels in the Deep South were a very significant part of the story. Then it happened again. And again. At what point does it begin to look like something more might be involved, especially when other species (our aforementioned Black- bellied Whistling-Ducks and Little Blue Herons, for example) seem to be undergoing very similar vagrancy patterns—though perhaps made less obvious by their wider distributions. This is the value of being able to look back, not just across a season nor even seasons, but across years. It is a valuable thing to be able to report on what happens in a season and to ruminate on why. Very often we will, rea - sonably and analytically, consider that an irrup- tion of Dickcissels into the east is the result of a drought or a northward wading bird flight is caused by water conditions. And we may well be right in these considerations. However, the only way to know this, or perhaps better to strongly suspect it, is to look back three, six, nine years down the line and see what else happened. I say this in preparation to make another housekeeping point. The Changing Seasons is a popular and venerable part of North Ameri - can Birds, but with some of the changes coming down the pipe (refer to the Editors' Notebook column) it won't look exactly the same as it does now. In the future, you can and should expect to keep finding review and analysis in this column. However, readers may discover that this column will no longer directly relate to the season that seems "relevant" given the journal issue. I put relevant in quotes because, as birders and spe - cifically, as birders fascinated with the world of status and distribution, we know that relevance is relative. In the right context, anything can be made relevant and topical again, and I hope that we can continue to demonstrate this in this col - umn in the future. Consider how it might look if, for example, The Changing Seasons were printed on a less-frequent basis—for the mo - ment, let's say annually—but it consisted of a deeper analysis, discussing status and distribu - tion across species, across years, and across ge- ography. Personally, I find it an exciting prospect, as it would serve, not just to tie together the year that was, but also to look forward to what might be on the horizon and how we understand bird populations in an ever changing world. n

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