I am finding it difficult to find definitive information on this subject, so will be intrigued to see if Martin can shed some light on the Covenham bird.
As Dunlin are among the most variable of shorebird species, with significant differences in morphology and size across their range. I wonder if it is possible to safely assign racial identity to a long-billed Dunlin.
It is known that throughout the regions Dunlin are found. They show a wide regional variation in bill and wing length, as well as overall plumage and body mass. Size differences also vary clinally across breeding longitudes.
With the smallest races in Greenland, increasing northerly across Europe and Russia, with the largest races found in Alaska and Canada.
Bill length in the largest Dunlin races may be around 30 percent greater than in the smallest and it appears to make a difference (Size does matter) when choosing a mate.
Studies in the late '80s, early '90s showed that Dunlin males were on average smaller than females and generally had shorter bills.
That Shorter-billed male Dunlin may be chosen by their partners in terrestrial habitats, as their short bills would be advantageous during male parental care, brood-rearing and possibly during their display flights.
Selection of larger sized birds with longer bills is probably associated with the production of larger eggs and being more efficient when feeding close to the shore in lakes or marine habitats, respectively.
This selection process may favour large females when competing for mates and food resources but can we also tell the difference in the field, when if/not also in breeding plumage.
Was it
Calidris alpina pacifica,
arcticola or
hudsonia maybe
Login
FAQ
Search
Yet!
