A?recent gull sighting has caused me to raise several questions for which I have no or few answers.
If gull ID's cause you to glaze over, now is probably the time to quit reading.
?
Yesterday, I observed and photographed this gull at the Asotin County Landfill for about twenty minutes.
?
https://www.flickr.com/photos/birddog/31812294875/in/dateposted-public/
?
https://www.flickr.com/photos/birddog/31774972506/in/dateposted-public/
?
https://www.flickr.com/photos/birddog/31018175383/in/dateposted-public/
?
One of the first challenges is to age the gull.
In this case, both the Ring-billed Gull and the Mew Gull have white tails with a black band until they are adult birds, at which time the tail becomes all white
Since this bird has an all white tail, one would judge it to be a non-breeding adult.
I'm assuming, perhaps incorrectly, that to achieve an all white tail requires a rather complete molt.
?Gulls of the Americas ?, Howell and Dunn? states that perhaps 13% of 2nd cycle?Mew Gulls and some RB Gulls ?obtain an all white tail during molt.
?
But this bird has no or few other adult characteristics of either RB or Mew Gull.
?
An adult RB should have a yellow bill with a black ring, yellow legs and a clear eye.
?
An adult Mew Gull should have a yellowish bill with no or little black banding, yellow legs and a dark eye.
?
Most experts, but not all,?I have consulted on this particular bird ID it as a RB Gull
?
My conclusion?is that it is a 2nd cycle Ring-billed Gull that has undergone a minority molt resulting in an all white tail and has not yet obtained yellow legs.
?
My final conclusion is that reliance solely on field guides will often result in very confusing ID problems.
?
Keith Carlson
Lewiston
--