Raptor migration in the Gulf of Fonseca

Swainson's Hawks migrating over San Lorenzo, Valle

Exactly one year ago, on 10 October 2012, I observed a large raptor flight in San Lorenzo, Valle. Thinking the same phenomenon would likely be visible at the same location a year later, Roselvy and I went down to the southern lowlands yesterday, where we visited the same site, and a few nearby birding spots.

Sure enough, when we got there, we found a sizable raptor flight in progress. Like last year, the flight consisted mostly of Turkey Vultures and Swainson's Hawks, with modest numbers of Broad-winged Hawks and a smattering of other species present. Unlike last year, most lines were far away from the salt ponds complex La Ostia, where we started our birding, so there we focused on the shorebirds present.

Wilson's Plovers

Those too were nearly the same species and number as last year! Last year I missed Stilt Sandpiper – yesterday two were present; and I missed (western) Willet – yesterday three were present. We missed Solitary Sandpiper yesterday, but apart from those differences, we observed the same species in more or less the same numbers as exactly one year ago.

Stilt Sandpipers

After an hour and forty-five minutes in oppressive midday heat, we bailed and looked for food, shade and a better view of the raptor flight at Restaurante Brisas del Golfo. There we observed a raptor line directly overhead, one further south crossing the Gulf, and one further inland over the hills. Although we didn't count, we estimated about 10,000 Turkey Vultures, 6,000 Swainson's Hawks and 500 Broad-winged Hawks to have been passing us during the one hour and forty-five minutes we spent there.

Swainson's Hawks

A final stop at nearby shrimp farm Culmavic added migrant Chimney Swift and American Kestrel to our list, as well as the locally common Clapper Rail.

Dots

A couple of posts ago, I grumbled about having seen so little hawk migration thus far in El Salvador.

Last Saturday, Roselvy and I went to a Maya archaeological site called San Andrés, in the Valley of Zapotitán, more or less halfway between San Salvador and Santa Ana. Here, we found beauty, tranquility and, atop "Estructura 4", a 360° view of the sky.

Structure 4 is the hill on the far right in this picture, behind the little tree. The other three hills are Structures 1, 2 and 3, which are off limits. Although not as impressive as Tikal in Guatemala or Copán in Honduras, San Andrés is an interesting place to visit, with remains of human habitation dating back 3000 years. Situated in the Central American Volcanic Belt, its history is one of settlements establishing themselves, growing, flourishing, and then being wiped out by a volcanic eruption, before the whole process starts again.

Between 10 AM and 4 PM, we watched thousands of raptors, mostly hawks and vultures, stream high overhead. In the morning, the flight was dominated by Swainson's Hawks, which can be seen in the picture at the very top. A few broadwings are also visible in that photo.

Turkey Vulture and Broad-winged Hawk were the other two abundant species, both of which can be seen in this picture if you click on it. The hawk on the left is something else, and if you want to try and identify it for yourself, go right ahead. I'll tell you what it is a little further down in this post.

In the afternoon, the flight was dominated by Turkey Vultures, with thousands streaming over. Scattered among them were Broad-winged Hawks, eight of which can be seen in this picture.

Other migrant hawks we noted were Zone-tailed Hawk (2), Mississippi Kite (12), American Kestrel (1) and Sharp-shinned Hawk (1). With non-migratory, resident raptor species Northern Caracara, Short-tailed Hawk and Roadside Hawk, we got to 11 diurnal raptors, two vulture species included. The 'mystery hawk' in the third photo of course is a Zone-tailed Hawk. Only superficially similar to Turkey Vulture, the bird stands out as different from TV's in a number of ways: wingtips pointier and swept back, tail longer and thinner, head bigger. In this photo, the zone-tail looks a lot smaller than the Turkey Vultures, but that's partly because it is flying higher.

To get a sense of where we were seeing all these birds, here is a relief map of western El Salvador. Right in the middle, below a small crater, is San Salvador. The crater belongs to Volcán de San Salvador. The two yellow cards halfway between that crater and a crater lake, called Lago Coatepeque, identify two archaeological sites, one of which is San Andrés.

We saw birds flying mostly due east, which would bring them a little north of Volcán de San Salvador. I posted our sightings to the national birding listserv here in El Salvador, and this yielded a couple more descriptions from people who had seen the same thing.

Winding down

The hawk counting season here in Veracruz is nearing its end, and the raptor flight this late into the season is dominated by the two species illustrated above: Turkey Vulture and Swainson's Hawk. We're still getting a few broadwing stragglers; Mississippi Kites have all gone through. Yesterday, an immature Zone-tailed Hawk was a late migrant, for most of them have passed too. Late in the season, we can still expect modest numbers of redtails, and probably some more Turkey Vultures. Migration of Swainson's Hawks will soon be over. Currently, the season total stands at almost 4.5 million birds, a sizeable improvement over last year when the count stalled at 3.3 million. An interesting sighting for me personally was a dark morph Ferruginous Hawk which sailed high over Cardel recently. A striking bird: a long-winged buteo with whitish flight feathers in the wings and tail, contrasting with dark brown body feathers and underwing coverts.

This is a Fork-tailed Flycatcher, a primarily South American species that is known to wander widely and will sometimes show up in the United States. Here in Veracruz, it is fairly common in cattle pastures near the dunes.

I'm looking forward to another Golden-cheeked Warbler field season in Central America, only three weeks away, and was pleased to note yesterday that the Micheletti administration in Honduras struck a deal with the ousted Honduran president Zelaya. Elections are scheduled for November 29, in which neither Zelaya nor Micheletti will be candidates. As the country returns to political stability after a coup last summer, it should be safe enough for us to do field work there.

Is this a good season?

We still have about 250-300 hours (or a little less than a month) of counting to do here in Veracruz, but with 2/3rd of the season and nearly 4 million raptors behind us, we have a fair idea how the majority of species did this year. (Please refer to www.hawkcount.org for exact numbers.)

Turkey Vultures for example, currently dominating the flights and clearly not done yet, are fairly numerous this year. We've already counted more TV's than last year and we're almost on a par with the 2006 total. We're now at 1.3 million. Some years the count reaches 2 million, exceptionally more (2.7 mil in 2002).

For Osprey, also still passing through although tapering off, 2009 is already the best of the last 8 years of counting.

Swallow-tailed and Mississippi Kites are early migrants; the last SK was seen on the 29th of September. The last Mississippi's are still passing, but in very low numbers now. The Swallow-tailed Kite had a fairly low season, while the season for Mississippi Kite was a little better than average. The current total of 135 Hook-billed Kites seems about average. Last year's total of 200 was the highest on record. For Northern Harrier this is a low year, although some may still pass. The accipiters also are having a low year, while 6 Common Black Hawks is about average for that species.

A Harris' Hawk was seen yesterday, the third for the season, which is still on the low side. Seen two days ago were 4 Red-shouldered Hawks - all in the same line and passing within 10 minutes of each other - and this makes their total 12, which is a good seasonal total. Numbers of Broad-winged Hawks this season are low, but not dramatically so, as last year. Bad weather in the last 10 days of September probably depressed the count results for that species. For Swainson's Hawk (pictured at top), however, this year is already the best year since 2005, and we're not done yet - they too are still moving through in good numbers. Another buteo that is doing well this season is Zone-tailed Hawk; this is already the second best year on record (only 2007 was better). For Red-tailed Hawk it is still too early to say anything.

This is one of more than 1.4 million broadwings counted this year. This is a juvenile bird.

The falcons were late this year, but we're catching up. We've had some good kestrel flights recently and the seasonal total for American Kestrel is getting there, although still on the low side. For Merlin the season is about average, while for Peregrine Falcon this is already the second best year on record.

In the unusual raptor department, there were of course the birds I wrote about in the previous blog entry. We've now also had a couple of White-tailed Kites in the lines that we presumed were migrants, and a couple of days ago a White-tailed Hawk. Last year we saw resident White-tailed Hawks occasionally from both count sites, and they were a common sight near the raptor banding station. This year they are curiously absent: the bird on the count was the only one seen this year anywhere in central Veracruz that I know of. Last year we would occasionally see resident Crane Hawks, but they too are absent this year. Resident raptors here this year are Short-tailed Hawk, Roadside Hawk and Gray Hawk (all three common), and Laughing Falcon, Bat Falcon, Crested Caracara, Snail Kite and White-tailed Kite (less common).

Yesterday, we also had the following raptor at the Chichicaxtle count site (see photo below). For those of you keen on sharpening their raptor ID skills, I'll discuss it first before telling you what it is. (As always on this blog, clicking on any photo will enlarge it for you.)

The bird was not close, yet close enough to observe various details regarding shape and even plumage in this photo. If you know upon just a glance what this is, you know your hawks pretty well. The counter who saw it first said "John, take a look at this, I have no idea what this is" and when I showed the photo last evening to other counters, they too were puzzled. I actually did know almost immediately what it was, and I'm tapping myself on the back here to make up for an earlier identification blunder yesterday, about which more later.

Well, what is striking about this raptor? The fact that it has short, paddle-shaped wings and a long, banded tail. This bird does not look like any of the raptors found in the US, and indeed it is a tropical raptor. In the field, my co-counter suggested Laughing Falcon, but this bird was bigger than that species, and this bird did not have a facial mask. Instead - and this is not visible in the photo but was visible in the field - the bird had a white collar around the neck. It's a Collared Forest-Falcon. Normally a secretive species that "does not soar" according to Howell and Webb, but there it was in the open, and of course soaring. Every once in a while, a bird will do something outside its normal behavioral repertoire.

So yeah, I was reasonably pleased with myself for knowing right away which raptor this was, especially a species you would not expect to see under those conditions. Earlier that day, though, I was alerted to a group of distant waterbirds, that were provisionally identified as Wood Storks. "Well," I said, intending to sound authoritative, "I think they're [American White] pelicans. Look at how they are kettling, all stacked on top of each other. Wood Storks are usually more level with one another in a kettle." I thought I had made a pretty strong case, and then when they streamed out in a line of long bows, I felt certain these were indeed pelicans, not storks. But as they got closer, they somehow morphed into Wood Storks! I felt like an idiot, for we have seen thousands and thousands of both species now - more Wood Storks than American White Pelicans, but still - and I should know how to tell one from the other. Up close they are very different; from a distance they can appear deceptively similar.


Here's a kettle of Wood Storks - ahem, no, I mean American White Pelicans of course, photographed a few days ago in Cardel...

Higher numbers continue

Good hawk flights continue here in Veracruz, with daily totals of at least 70,000 raptors for four consecutive days.

Broadwings and, to a lesser extent, Turkey Vultures dominate the flight this part of the season, while Swainson's Hawks are seen daily in low numbers.

We also had a good Wood Stork flight yesterday, with 3,110 migrants counted. After a long day of travel, these three were looking for a place to spend the night.