ENDANGERED SPECIES ON ABACO, BAHAMAS (2): KIRTLAND’S WARBLER

The rare Kirtland’s warbler (Setophaga kirtlandii) is rightly prized both in its very specific breeding grounds and in its winter migration locations. Abaco is fortunate to be one of these, but they are extremely difficult to find, even with local knowledge. The latest IUCN Red List assessment of numbers of adult warblers (2018) gives a figure of 4,500 – 5,000. The species is categorised as ‘near-threatened’. Numbers are gradually increasing, thanks to a major recovery plan and intensive conservation measures in areas where they nest. 

WHERE THEY LIVE

SPRING & SUMMER Mostly, the KIWA population lives and breeds in very specific areas of Michigan and Ontario, where jack pines are found. As numbers have increased, the range has expanded more widely into Wisconsin and Ohio.

A Kirtland’s Warbler in the jack pines of Michigan (Vince Cavalieri)

FALL & WINTER the population migrates to the Bahamas & TCI, where they tend to choose remote scrub and coppice areas to live until the spring when they return north in April. This range map shows the extremely specialist habitat choices of these migratory birds.

THE MAIN THREATS TO THE SPECIES

• Mankind is the primary threat. The breeding areas are particularly vulnerable from deforestation and clearance of the jack pines that are essential for successful nesting and breeding – and therefore the survival – of the species
• Encroachment by development is a major concern (as with so many species everywhere)
• KIWAs are vulnerable to nest parasitism by brown-headed cowbirds in the breeding areas
• Their winter habitat is mostly in remote or protected areas, but on Abaco a proposed development in the National Park where they live will probably wipe them out, if built   
• Overall, habitat degradation at one end of the migration – in particular the breeding grounds – poses a serious risk to the species; at both ends, extinction could loom again

WHAT TO LOOK OUT FOR?

• Gray head with a blueish tinge, gray-brown back
• Yellow throat & underside, with some dark streaking
• Females are paler and more streaked
• Split eye rings – white crescents above and below eyes
• Frequent tail pumping and bobbing

WHAT DO THEY SOUND LIKE?

Some say ‘chip-chip-chip-too-too-weet-weet’. Elsewhere I have found it claimed that they produce ‘a loud tchip, with song an emphatic flip lip lip-lip-lip-tip-tip CHIDIP‘ (Arnott). I’m not a big fan of phonetic spelling for bird sounds. Here’s a sample for you to assess:

 Ross Gallardy / Xeno-Canto

WHO WAS MR KIRTLAND?

Jared Potter Kirtland (1793-1877)

Jared P. Kirtland (1793 – 1877) was an Ohio scholar, doctor, judge, politician & amateur naturalist. He was a man of many and varied interests and talents, not-untypical of his time. In the field of natural history, Kirtland’s name lives on in his warbler & also in a couple of snake species.

The Bahamas Postal Service is commendably active in producing wildlife stamps