Mystery Warbler Solved?

Cape May warbler, courtesy of Greg Lavaty

As a novice observer of birds here in Costa Rica, I made a tentative start back in 2007. My first real migration season occurred the next year. Several species caused identification problems, but none more so than a warbler that appeared in my garden on at least 6 occasions. Here are my first notes from that migration period 2008-2009:

2008, November 17

mystery warbler, fairly slow but not a vireo. Heavy streaks all over a pale yellow breast; slight eye-line, otherwise drab, whitish below

2008, November 18

Same bird, now also on the ground; white spot in tail, I believe; Cape May still seems most likely

2008, November 23

Same bird, blurry streaks, touches of yellow on flanks and maybe throat; repeated chipping like a Yellow warbler, but there could have been one in the same tree

2008, December 5

Excellent views; grayish with yellow wash on breast overlaid with heavy streaks; white tail edging; sharp beak, short tail and dumpy-looking; literature says it’s a rarity, but I’ve now seen it several times here

2009, January 8

I remain utterly uncertain about the identity of this bird; it has strong black streaking on sides and less strong streaking on the breast; it has yellow on the breast, no distinguishable yellow or black on the head; some white in the tail is not very obvious. It suggests a Black-throated green warbler, but the head seems grey; no streaks on the back, which eliminates Blackburnian; I have no clue

2009, January 13

Same bird again; yellowish wash on breast; heavy streaks, less so down the middle

Here’s more or less what it looked like:

A drab first-winter Cape May warbler

I saw the same bird subsequently on at least one further occasion, just a glimpse really, on my walk down to San Diego, but this morning, some 5 years later, I had a clear view of the same warbler as it sipped nectar in the nearest bottle-brush tree in the San Antonio churchyard, right opposite my gate. It was accompanied by at least two Tennessee warblers (Vermivora perigrina), which is probably the commonest migrant warbler here in our area. My little camera has no chance of recording warblers and so I’m still short of a photo id, but this time, in addition to taking notes, I consulted internet photos of the Cape May warbler (Setophaga tigrina) and found that several match my mystery bird very well.

The lead photo is closest to this week’s individual in the San Antonio churchyard.

A male with a chestnut face would be a clincher, but no such luck of course. This morning’s bird had yellow on the face, but otherwise matched my previous descriptions. This time I also noted the streaks on the upper breast, a yellowish rump, a single slim wingbar and some white in the tail in flight. The excellent series of photos in the Cape May Warbler Photo Gallery by Greg Lavaty at pbase.com shows just how varied the species can appear, depending on whether it’s a male, female, or first-winter bird.

Here’s a male in breeding plumage.

Male Cape May warbler shows the chestnut face patch

Update: Heavy rain falls all the next day, but I’m in luck! The bird appears late afternoon in the same bottle-brush tree, this time with a handsome male Blackburnian warbler nearby. This time I got so close that I could even have taken a photo with my midget camera. I can try again tomorrow. I’m hoping in the meantime that someone may come to my aid with some information on Cape May warblers in Costa Rica. Greg Lavaty very kindly has given me permission to use his photos, all taken, I believe, in the United States. Check out his beautiful photos at http://www.pbase.com/dadas115/profile

Let’s finish with a shot of a Blackburnian warbler, taken here in the garden a few years back. Unfortunately, I still have the same low-grade camera!