Saturday, December 8, 2018

Warbler Guy, did Kirtland's Warbler again nest in Wisconsin this past breeding season? — as I know it previously was a Michigan breeding endemic only in the USA. Is Kirtland's Warbler still federally endangered? Kirtland's Warbler breeding range is expanding?

Donnie (in N. Dakota):
Beyond staying warm, I hope to heat up your interest in the ongoing fascinating Kirtland's Warbler (KIWA) progress as it rebounds from near extinction to more robust total population numbers — given, "yes" this federal endangered species (via the US Fish & Wildlife Service) (USFWS) was again detected to nest in not only Michigan and Wisconsin in 2018, but also in one spot within Ontario, Canada.

(Photo courtesy of Dennis Maleug)

Read on, as this avian tale gets more interesting (sorry for the pun....):

1. First, did you know that before starting its Phoenix-like comeback from the brink of extinction, KIWA's entire worldwide population dropped to 167 breeding pairs in Michigan in 1974 (PLEASE feel free to see the below graphic)?

2. Then this 4.5" wood-warbler (that spends the non-breeding season ONLY among Bahama islands), began its upturn in population after conservation group and government agency partnered, thereby implementing long-term management actions to conserve young jack pine habitat that KIWA favors for breeding grounds. In addition, management actions reduced Brown-head Cowbird numbers, a brood parasite known to reduce several North American songbird order species population numbers, including KIWA. (i.e, Brown-headed Cowbirds lay their eggs in warbler nests; larger cowbird chicks outcompete their warbler nest mates, causing the warbler chicks to die while the unwitting warbler parents raise the cowbird imposters.)

3. In turn, responding to managment actions, KIWA's population rose dramatically (again, see the graphic, below), helped by a tragic fire that killed people, but also resulted in ideal suitable breeding habitat for KIWA. The result: KIWA numbers reached more than 1,000 pairs by 2001, expanding beyond the northern Lower Peninsula to areas in Michigan’s Upper Peninsula, Wisconsin and Ontario. 

4. Currently, the Kirtland’s warbler population is estimated to be over 2,000 pairs, more than double the recovery goal identified in the Kirtland’s warbler recovery plan established by the USFWS. The population has exceeded recovery goals for the past 20 years and continues to increase and expand its range.

5. More information will soon follow to answer:

How did breeding KIWA do in Wisconsin in 2018? Answer: OK, with the WI DNR noting in a news release that KIWA nests were found in at least two counties throughout the state. 

Note the final 2018 KIWA results were not available from the WI DNR when I wrote and updated this article on 12/19/18. Therefore, I share in the next paragraph the 2017 breeding results for KIWA in Wisconsin (See: Please check back soon for the 2018 KIWA breeding success update in Wisconsin.

In 2017, the Kirtland’s warbler nesting season marked the 10th year of Kirtland’s documentation and subsequent monitoring in Wisconsin. From only 11 Kirtland’s and three nests found in Adams County in 2007 to 53 individuals and 20 total nests among Adams, Marinette and Bayfield counties in 2017, the population has grown and geographically expanded in our decade of conservation work. 

Regards, Daniel 

Certified Wildlife Biologist Asc. and Avian Biologist 

(hosts my resume and Birding Guide and Birding Tour services......... given I have led tours since 1985).

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