Thursday, June 25, 2009

Can I count it?

Trumpeter SwanMost Trumpeter Swans in the Pacific NW are wild migrants. However, I learned that these at Brownsmead, Oregon on 31 December 2007 were pen-raised and released locally, thus "uncountable." Photo by Greg Gillson.

 

One major aspect of "birding" for many people is "listing," keeping track of the bird species that one has seen. These lists can be life-time lists, state lists, backyard lists, year lists, etc.

One question that arises is: "What birds can I count?".

Mary and Jim in Salem, Oregon posted such a question to the Oregon Birders OnLine (OBOL) email discussion list on 24 June 2009: "We saw a Mute Swan in McGilchrist Pond in Salem this afternoon. Are they "countable" for our life list?"

One response included the predictable: "You can count whatever you want, It's your list."

Of course, this is true. But Mary and Jim would not have asked if they were just going to make up their own rules about what they counted. They wanted to know about generally accepted rules about what others consider countable. There can be some healthy competition among the top listers. But even if comparison with others is not your goal, reaching a personal landmark of a list of 200 or 300 or 400 species in one of the Pacific NW states is quite an accomplishment.

Who makes up the rules? In the United States and Canada there is an organization called the American Birding Association that appointed itself the maker of bird counting rules. While this may seem brazen, most birders adhere to these rules because they provide a standard and, well, they just make sense.

For instance, the pertinent rules about counting a bird on your North American list (if you wish to conform strictly to the ABA rules) are basically as follows.

(1) The bird must have been within the prescribed area.
(2) The bird must have been a species currently accepted by the ABA Checklist Committee for lists within its area.
(3) The bird must have been alive, wild, and unrestrained when encountered.


For Jim and Mary's Mute Swan, the question comes down to the "is it wild?" requirement. Since Mute Swan is not a native bird to the Pacific Northwest, we'll assume that the Mute Swan they saw in a park in Salem is not a vagrant wild bird from Eurasia but, rather, an exotic release or the offspring of recently released birds. To answer this "wild" question the ABA has a whole page called Criteria For Determining Establishment of Exotics.

The particular guidelines to note are the requirements that the population of exotic birds is self-sustaining, not directly dependent upon human support, and present for at least 15 years.

Clearly, a single Mute Swan or even a pair or two does not meet the criteria for an established exotic. Even worse, there is a special rule specifically mentioning Mute Swans as an invasive species that is not likely to become self-sustaining because of active control efforts to eradicate any emerging populations.

So, by ABA rules, the Mute Swan seen in Salem is not countable.

By these rules, many Rock Pigeons probably should not be counted (free-flying birds raised by pigeon fanciers). Most populations of Wild Turkeys technically don't meet the 15 year establishment criteria in the Pacific Northwest. Ring-necked Pheasants may not be self-perpetuating west of the Cascades, even though they have been part of the avifauna for a century.

But it's nothing to get dogmatic about. After all, "it's your list," right?

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