Saturday, December 13, 2008

eBird Frequency Bar Charts Updated

For those of you who are eBird users, you may already know about this new bar chart update. And for those who are not eBird users, well, you should think about giving it a try (especially now that you'll be out and about or looking from your home windows at the feeders) for Christmas Bird Count season is upon us.

Also, non users should know about these eBird functions because they are a very valuable source of info not only to the local birder but to the traveling birder as well. Often birders who come into or call the Northwood Center are looking for info on what species they may be likely to encounter in the field during their visit. More often than not I pull Sibley's Birds of Cape May off the bookshelf and show them the frequency bar charts in the back. While the bar charts in general don't change significantly over the long haul (though I've read much in recent years about observations of some species timing of migration changing slightly) the textual accounts which include maximum counts, early and late dates does need some updating.

In the past to access this type of frequency information for a given location you would have to pick up a book while at the birding destination or call ahead to place an order. And, often no such bar charts exist to be referenced. Of course now with listservs you can seek information from other birders in a specific location via email or, with eBird you have all of the same information provided in these wonderful reference books, accessible at the click of a mouse. But there are a couple of caveats at this point with the eBird program.

As I've stated before, the more users who are inputting data, the more robust the data set. You don't have to have a PhD to know that this is the case. So if you are looking for frequency data on some areas that are not as popular as others, the charts my not be fully representative of the bird life in the area. The eBird team explains this a bit and how their frequency histograms work, on their site.

The second issue is the dates for high counts, early arrivals and late departures. While it may be the case that the more recent data entered into eBird is the more accurate, there is the issue that much of the historical data has yet to be integrated into eBird and possibly never will. Take Cape May for example, the high count for American Kestrel is listed at 1,031 birds on 9/23/2007, on eBird. If you look at Birds of Cape May you'll find the number of 24,875 from 10/16/1970. In this case the newer counts are the more accurate since Kestrel numbers have been plummeting. You can't, unfortunately, come to Cape May in late Sept. to early Oct. and expect the huge falcon flights of the past.

None the less, it's worth taking a look, at least at the county level for frequency information. At the very least this information should help to make you a much more informed birder when planning your next outing, whether near home or even across the country.

No comments: