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Observing Ospreys

October 3, 2013

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For years, birders in South Florida have reported occasional birds resembling the Caribbean race, “Ridgway’s” Osprey (Pandion haliaetus ridgwayi). However, a major problem with confirmation is that “Ridgway’s” Osprey characteristics are not well understood or described in the popular literature. Plus, the academic community has never been able to ascertain any undeniable evidence such as a specimen or DNA from one of these birds to prove definitively that this subspecies occurs. As such, without this precedent the professional/academic community remains cautiously skeptical.

In the definitive work “Birds of North America Online” Osprey species account authors Alan Poole, Rob Bierregaard, and Mark Martell write, Caribbean breeders noticeably paler on crown and breast than their North American counterparts, appearing almost white-headed and white-breasted and showing little difference between male and female. Occasionally paler individuals, like Caribbean breeders, found breeding in s. Florida… suggest, perhaps not surprisingly, possibility of limited interchange between Caribbean and North American populations…” Link: http://bna.birds.cornell.edu/bna

Again from the BNA account the subspecific description of “Ridgway’s” Osprey reads:

P. h. ridgwayi – Maynard, 1887; type locality Andros I. Resident in Caribbean from Bahamas and Cuba south to coast of se. Mexico and Belize; not currently found breeding south of s. Belize and Cuba. Under wing primary-coverts mostly white with pale brown restricted to distal two-thirds of outer web; head largely white (dark markings reduced on crown and sides of head); breast markings reduced or lacking on both sexes; relatively small (averaging smaller than P. h. carolinensis). Often paler brown dorsally (perhaps sun bleaching).

Despite the reservations of some, here I summarize three individual, independent sightings of a bird (or birds) that fit the bill for a Ridgway’s Osprey from the middle Keys near Marathon, FL in 2013 – all with supporting images. The first report was from a Victor Emanuel Nature Tours (VENT) trip led by Michael O’Brien and Louise Zemaitis on 30 April 2013. The bird was perched on the concrete edge of the Seven Mile Bridge just south of Marathon on Route 1. Stopping here is impossible, but tour participant Jeff Haller managed the image below which was included in an eBird report here: http://ebird.org/ebird/view/checklist?subID=S14015903

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Photo by Jeff Culler, April 30, 2013, 7 Mile Bridge, Marathon, FL.

In the notes for this sighting, O’Brien writes that this was the 3rd sighting of this bird (twice in this exact spot); and as you can see from the report, he lists this as “Osprey (Caribbean).” In the photo above, one can get a sense of the greatly reduced, dark eye line – appearing as only a comma-shaped mark starting behind the eye and on the auriculars. Also a sun-bleached appearance is evident.

Last week during the Florida Keys Birding & Wildlife Festival, FKH director Rafael Galvez and David Simpson (Birding with David Simpson tours) spotted an Osprey flying over with a nearly full white head during the “Morning Flights” field trip at Long Key State Park on Thursday, September 26th. They described it as having just a tiny smudge of dark in the auriculars. Participant Eran Brusilow with Disney’s Animals, Science, & Environment managed to capture the image below as it streamed by. Rafael told me about it on the phone as I was driving toward the keys Thursday afternoon. Being a bit of a raptor plumage nut, I was disappointed to have missed this bird so narrowly, but was still excited to see the images. So upon arriving in the Keys I tracked down Rafael, David, Eran and Tricia Emrich, and was shown the image below.

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Photo by Eran Brusilow, Long Key State Park, Long Key, FL – 26 Sept. 2013.

While it was hard to assess the extent of dark on the face given the angle, I was immediately struck by the amount of light buffy markings through the carpal patch (dark mark at wrist on underwing). Unlike the typically solid, dark block that I’m used to seeing on the local Florida birds, this bird showed a real checkered pattern with a much interspersed buff that seemed immediately outside the range of typical variation of the Ospreys I see daily (P. h. carolinensis).

In looking at photos online of Osprey photographed in the Caribbean, it does appear this mottled, “salt and pepper” carpal patch is not uncommon for “Ridgway’s” Osprey, so this may be a trait to look for also, as we continue to learn more about these birds.

I spent the rest of the weekend in the central Keys enjoying the incredible 429 Peregrine Falcon day on September 27th (a marvelous spectacle) and as always had a great time soaking in the fabulous fall migration. As all good things though, my time here came to an end. So near 2 PM on Sunday afternoon, I bid a final adieu to Kerry and Rachel, Rafael and the marvelous volunteers and visitors at the watch and began my trek northward. Ten minutes later, shortly after passing Long Key State Park I saw what appeared to be an adult Bald Eagle on the radio tower in the little town of Layton. As I sped by I realized I was dead wrong. So I quickly spun around and parked on the side of the road. I quickly mounted my spotting scope on a window mount and began digiscoping another or the same light-headed Osprey. In total this was roughly 25 miles north of the April sighting and a mere 1 – 1.5 mile north of the bird seen 4 days earlier by the FKH crew.

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Probable “Ridgway’s” Osprey, digiscoped Layton, FL – 30 September ‘13.

The photo above is a bit soft but it is a similar pose to the April image allowing better comparison of the shape & extent of the dark head markings. The second image below is sharper and more in full profile, allowing one to better appreciate the extent of the facial markings. Note the light area between the rear of the eye and the beginning of the dark “swoosh.”

Digiscoped by J. Bouton, Leica V-lux 40 camera thru Leica APO Televid 65 mm scope.

Digiscoped by J. Bouton, Leica V-Lux 4 camera thru Leica APO Televid 65 mm scope.

Compare with a typical Osprey below also photographed in the Florida Keys in October 2012. Note the width and extent of the dark eye stripe and the dark through the center of the crown as examples.

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For comparison, a more typical Osprey (likely male) photographed in the Middle Keys, Oct 2012.

Elated to have NOT missed a chance to see a probable “Ridgway’s” Osprey after all, I continued home with my buddy Travis, getting him some additional life birds along the way – of course that’s another story!  ;p

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