It’s been an unbearably hot summer for many of us across North America, but something odd is afoot with the occurrence of Asian and European shorebirds this July.Compared with previous years, 2012 is shaping up to be a banner year for many of these rare shorebirds. With fall shorebird migration just beginning to heat up, reports of many rare species are coming in from both coastal and inland locations. July is historically a good time to find odd Asian shorebirds, but August and September are also great, so be aware this year, get out there and scour your local mudflats for something unusual.
Ruff is one of the more frequently encountered Eurasian shorebirds in North America, and July 2012 has been the best year in recent memory for finding this species in North America.
This map shows Ruff records reported to eBird within the last 30 days (taken 24 July 2012). Contrast this with the maps below for 2011 and 2010, when just one and two reports were made respectively.
Little Stint is another bird to watch for. So far in July 2012 two have been recorded in eBird in New England (Rhode Island 4 July and Massachusetts 21-22 July) and one in California (another was found 24 July, but isn’t in eBird yet!); last year there were three in July in California, but in 2010 there were none reported in the Lower 48. Several Red-necked Stints have been found in Alaska this July, as well as one in Oregon and one in Kansas! These vagrants are possible anywhere, so keep a sharp eye out for these mixed in with the throngs of our regularly occurring “peeps”.
Other MEGAs recorded this July include Black-tailed Godwits in Delaware and Texas, a Spotted Redshank in Oregon, a Common Greenshank in British Columbia, and multiple Curlew Sandpipers.
It should be noted that while some species, such as Red-necked Stint and Sharp-tailed Sandpiper, have obvious Siberian origins, others (e.g., Little Stint, Ruff, and Curlew Sandpiper) could be reaching North America from Siberia or from western Europe. The route taken to North America for Eurasian shorebirds (such as Ruff and Curlew Sandpiper) has been long debated, but their relative frequency on Barbados and other Windward Islands in the Caribbean demonstrates that a healthy number do cross the Atlantic on the trade winds that blow from Africa to the Caribbean and northeastern South America. That said, the regularity of Red-necked Stint in the East, and the extreme rarity of most western European shorebirds (e.g., Eurasian Curlew, Common Redshank, etc.), may suggest that many more East Coast shorebirds have Siberian origins than has been previously thought.
Interestingly, 2010 was generally good for Eurasian shorebirds in the East, 2011 was good for them on the West Coast, and 2012 is shaping up to be good for them nationwide. Exactly what governs these vagrant shorebird influxes is not clear, to us, at least. It may be that the orientation, strength, and position of the polar jet stream contributes to the arrival of these species into North America. A more thorough investigation is clearly necessary, and eBird data may help to make that possible!
One thing is certain: this July is shaping up to be one of the hottest months on record for Asian vagrant shorebirds, and there’s no reason to think it won’t continue into August and beyond. Get out and check your local patches, and make sure to report all your bird observations to eBird!
Team eBird–July 2012
Article source: http://ebird.org/content/ebird/news/vagrantshorebirds2012Share on Facebook