Ontbirders: To add to your understanding and hopefully enjoyment of the Thick-billed Kingbird that I hope you all have seen or will see, I am posting my observations and thoughts on this bird’s age, sex, plumage and origins.****
** ** I, along with several others, had thought that the Thick-billed Kingbird was an adult in worn plumage. However, after consulting Peter Pyle's "Identification Guide to North American Birds Part I", and perusing the number of excellent photographs posted on-line of this bird, I have come to the conclusion that this is actually a hatch-year bird in pre-basic molt.*** * ** ** The extensive pale yellow of the lower belly and undertail coverts, along with the brownish wings and uppertail coverts and greenish tone to the back strongly suggests this age group. Adults show less yellow with blackish wing coverts and a mantle without the greenish tones.**** ** ** Its gender is very difficult to deduce, especially for a hatch-year bird so I will not hazard a guess, except that vagrants are often males and for that matter, hatch-year birds.**** ** ** Often, birds still in fresh juvenal plumage show little feather wear leading one to think that it was worn adult. The heavily abraded rectrices (tail) and secondary / tertial / greater covert (flight) feathers of this individual indicate it is in advanced molt from juvenal to pre-basic plumage. This molt is concluded on its summering grounds, which have now become **Ontario** rather than its normal **Arizona** / ****Mexico**** location!**** ** ** It is likely that it will not resume any long distance travel until its pre-basic molt is complete. By the same token, it may have arrived in the north-east some time ago, when its molt was much less advanced.**** ** ** The Thick-billed Kingbird’s normal summer range stretches from extreme south-eastern **Arizona** (mainly the Patagonia area) and south-western **New Mexico**, south through **Mexico** to ****Guatemala****. Most birds in the **U.S.** and **Northern Mexico** start to move south in August and are gone by mid-September.**** ** ** This Kingbird is likely a reverse migrant, this occurs when its internal navigational system is compromised and it migrates 180 degrees to its normal direction i.e. north rather than south. It may also have been assisted by the clockwise movement of weather systems ahead of Tropical Storm Isaac. **** ** ** You may recall the Black-throated Sparrow that made a brief appearance a few years ago at the same time of year at Pt. Burwell. This was also likely too a reverse migrant.**** ** ** If you would like to comment please e-mail me privately.**** Alfred Adamo York alfred.ad...@gmail.com ** _______________________________________________ ONTBIRDS is presented by the Ontario Field Ornithologists - the provincial birding organization. Send bird reports to birdalert@ontbirds.ca For information about ONTBIRDS visit http://www.ofo.ca/
