[CT Birds] Hybrid Gull

Paul Cianfaglione pgcianfaglione at gmail.com
Wed Mar 26 16:49:59 EDT 2014

First, I would like to thank Patrick Comins for taking the time to really
study my reported Black-headed Gull. The subtle differences pointed out by
Patrick certainly confirms his keener eye for gull identification than
mine! However, I would like add a few of my own comments regarding this
possible hybrid. While the bill and leg coloration and hood are all good
Black-headed Gull field marks, the overall size of the gull, bill size and
dark mantle were called into question. Given that this is a gull, Sibley's
guide adds a word of caution to its "small hooded gulls" plate;

  *Variation in structure and plumage in these species, as in all other
gulls, is dramatic. Careful study of flocks will reveal exceptionally
large, small, light, and dark individuals that may cause confusion when
seen singly.*

As far as the wing mirrors go, variation may come into play here too, or
maybe that both P9 and P10 are partially covered by adjacent feathers in
the only available photo.

Before a hybrid can be said for certain, I believe there needs to be more
photographic evidence. I will wimp out here and refer to the law of
parsimony which states;

*the principle in philosophy and science that assumptions introduced to
explain a thing must not be multiplied beyond necessity, and hence the
simplest of several hypotheses is always the best in accounting for
unexplained facts.*

Paul Cianfaglione


More information about the CTBirds mailing list