The Variability of Spring Migration Timing

Having been following along with the way weather impacts the arrival of certain migrants for a number of years now, I want to take some time to compare the ways spring migration has progressed over the last seven years. For the sake of the amateur birders/nonbirders that follow this site, I will refrain from getting technical about weather. In the future, I hope to make another post on this subject using historical weather data, but for now I will stick with my broad qualitative observations.

2010 was really the first year that I fully grasped the fact that weather has a direct impact on the quantity and diversity of neotropical migrants seen on a given morning, thus making it a logical place to start. I was a very active birder in 2009 and before, and enjoyed warblers and others thoroughly, but don’t recall following the weather in order to ascertain the numbers of birds moving and to plan my outings.

Because 2010 was the first year I was doing this, it is the year I sometimes use to compare the others to. Back then, I was going through rigorous treatment (and even had a major surgery right in the heart of spring migration), so my birding outings were limited. What strikes me most about 2010 is that it was kind of ‘normal’ (obviously, this observation needs to be backed up with data, which I will hopefully be able to do soon). We had our first major push of birds in late April, with diversity peaking in the NYC region by the middle of May.

2011, by contrast, was marked by a surprisingly early and strong start (beginning in the second to last week of April), before giving way to unfavorable winds for the beginning of May. Things turned back around (as they always do) by the middle of the month, with Blackpoll Warblers descending on the Northeast en masse by around the 15th.

2012 was a lot like 2010. Migration progressed in a fairly even manner, with the first big days occurring during the first week of May. It was my most memorable year for observing spring migrants; I went birding after school virtually every day, and really got to appreciate the subtle (and not so subtle!) changes that occur daily during the height of spring migration.

2013 was at times frustrating. It got off to a strong start at the end of April (much like 2011), before giving way to almost a week of sustained easterly winds to start the month of May. That was followed by a nice rebound in warbler diversity, but for me, the birding didn’t approach that of 2012.

It think the result for 2014 is almost predictable now. It was a lot like 2012 and 2010 (at least for me). It was right there with 2012 as being a really fun year for enjoying spring migrants, capped off by a Fairfield Big Day that recorded 23 warbler species, including a Kentucky.

I recall 2015 as being possibly the worst of all these years. Which is funny, because just to our north, my friend Dave Hursh reported having the best spring migration experience of his life at Mount Auburn Cemetery in Cambridge, Massachusetts, recording 20+ warbler species daily for almost three weeks.

2016 has gotten off to a fascinating start. Birds began to trickle through the closed floodgate (as they always do) during the last ten days of April. Then came a horrible period of eight straight days of overcast rainy weather, with unfavorable winds unyielding. Finally, things changed on the night of Saturday the 7th, with a massive coastal fallout occurring in SW Connecticut the next morning, as some of the lingering rain collided with impatient migrants in the first big night of migration of the season. Reports came in of 20+ warbler species from Stratford, New Haven, and elsewhere, with birds often keeping close to the ground and being quite tame. At the moment, there is a Nashville Warbler loudly singing outside my window, with an American Redstart joining in from across the street. I look forward to following the continued progress of Spring Migration 2016, which will hopefully follow along with its even-numbered predecessors!

Note: these are simply my observations, and thus your experiences may have been completely different. Was 2012 a paltry year for you with 2013 breaking all records? If so, definitely share your experiences in the comments section below.

-Alex

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