Wednesday, March 28, 2012

Hummingbird progress

I saw an email today from Bill Hilton in South Carolina, reporting his first Ruby-throated Hummingbird of the year from Hilton Pond. This bird was one day later than Bill's earliest record, and pretty much right on schedule for that part of the country. Bill, by the way, is one of the country's premier hummingbird researchers, and you should check out his wonderful website HERE.

This prompted me to check the eBird data chest to see their map of the hummers' northward progression.

Here it is, showing hummingbirds starting to penetrate to the latitude of Tennessee, with one southern Indiana record. Still a ways from Ohio, although we did have one credible report from an experienced observer a few days ago. Insofar as I am aware, that would best the previous early Ohio record by over two weeks. I do think hummers may appear here a bit earlier than normal, and we should start to see some more reports within ten days or so.

You may recall that I recently blogged about a site that annually posts a hummingbird migration map, HERE. I expressed incredulity over that map's spate of northern records (CLICK HERE for their latest map), and I remain quite skeptical of's map. Since then, someone sent me another website's hummingbird migration map, HERE. It also has plenty of groundbreaking records.

These maps have drawn plenty of skepticism, and commentors responding to the skeptics seem to fall into two camps: 1) those of us who doubt the maps/records are saying that the reporters who contributed the maps' records are liars; or 2) eBird reporters and other observers just must not be finding these early hummingbirds.

I don't believe either of those answers is correct. I believe that all, or nearly all, of the weeks-early northern records that makes up those non-eBird maps are cases of misidentifications. Our exceptionally warm late winter and spring has seen a very early emergence of large insects that normally would not yet be on the wing, such as carpenter bees, green darner dragonflies, and various big sphinx moths. And believe me, people can and do mistake these large bugs for hummingbirds. If someone does spot an honest to goodness hummmingbird that is weeks early, they should try to document its identity to ensure it isn't one of the potential vagrant non-Ruby-throated species. There is nothing wrong with questioning the out-of-the-ordinary, and wanting to see solid evidence for significant new trends, such as hummingbirds appearing weeks earlier than they've ever been reported.

Anyway, the eBird map draws on carefully vetted records and is reliable. I think it provides us with an accurate picture of this spring's hummingbird migration thus far.

No comments: