Wes Jansen wrote:

> Several "North American" bird books I've seen only list birds found =
in
> Canada and the USA. Is my geography off, or does North American =
actually
> include all countries down to Panama?

The format of the several "Birds of North America" volumes and =
identification guides was based on the AOU check-list. In previous =
years, the AOU limited its scope to the Birds of Canada and the US, Baja =
California, Bermuda and Greenland.

The American Ornithologists' Union included in its 1983 "Check-list of =
North American Birds" the species of Birds of North America from the =
Arctic through Panama, Including the West Indies and Hawaiian Islands. =
In the preface, the authors wrote about 2 pages on Geographic Coverage, =
and defended their reasons for including the birds of Middle America on =
(and for excluding the birds of Greenland and the Lesser Antilles from) =
the 'North American' list.

"North and Middle America are part of a continuum in terms of physical =
geography, but the tradition in American ornithology has been to discuss =
these as distinguishable regions...primarily for practical convenience." =
As most of Canada and the US lie in the Temperate to Arctic zones, it =
previously made some sense to limit 'North America' to those countries. =
The 6th Check-list includes the birds south of the Mexican border =
because Temperate Zone "conditions and habitats extend south in higher =
altitudes into tropical latitudes..". A number of 'North American' =
species have close relatives south to the Isthmus, and it really helps =
put taxonomic relationships in perspective if you consider the Collared =
Towhee as kin to the Spotted and Rufous-sided Towhees, for example.

Birds in the West Indies tend to be evolved from colonizations of birds =
from temperate N America and tropical middle America, with a lesser =
degree of colonization from South America which has evolved a more =
distinct and diverse avifauna because of its relative isolation.

Hawaiian birds were included because, of course, Hawaii is one of the 50 =
US states and federal bodies and agencies use the AOU check-list as a =
standard reference in matters pertaining to birds.

Greenland was dropped becaue it has no endemic species and has a =
European (Palearctic) component to its avifauna that wouldn't have made =
it onto an 'American' list were it not for the Greenland connection. =
Trinidad and Tobago (Lesser Antilles) have avifaunas with strong South =
American affinities.

Anyway, I kind of like to think of the North American avifauna's =
ecosystem as including their southern cousins' turf. Besides, that's =
where so many of 'our' birds go in the winter. When it's cold and =
raining, I think I might like to join them.......

Jon. Anderson
Olympia, Washington
festuca at olywa.net