Subject: [Tweeters] Re: STGU provenance
Date: Sep 2 12:00:13 2017
From: John Puschock - g_g_allin at hotmail.com
After posting to Tweeters last night about squid and Swallow-tailed Gull breeding behavior, I realized I missed talking about how The Gull could have ended up in the North Pacific.
On the webpage about the California Bird Records Committee vote (http://creagrus.home.montereybay.com/stgu_votes.html), Don Roberson connects the occurrence of extralimital Swallow-tailed Gulls to El Ni?o events. The El Ni?o of 1982 was very strong, causing many birds to disperse. Roberson suggests that perhaps a gull flew off to the northwest to the North Pacific, where it wandered for several years until was found in California in 1985. Then, he writes, "The bird behavior suggests it was responding as if on the breeding grounds."
The last El Ni?o event of 2014-2016, like that of 1982, was one of the strongest on record. It's occurrence in North America also could be explained by Roberson's hypothesis. The two events are strikingly similar.
John Puschock
Matthews Beach, Seattle