Wednesday, November 25, 2009

Rufous-naped Wren

In the Old World, there is only one wren - the Wren, or more properly Winter Wren, Troglodytes troglodytes. It is small, and a superb singer. In North America, more wren species are found, but the family achieves its greatest diversity in Mexico and Central America. No fewer than 34 species are found in this region, some with extremely small ranges. A bird with a relatively large range is this Rufous-naped Wren, a large cactus wren, i.e. belonging to the genus Campylorhynchus.

Within its range, mostly on the Pacific Slope from Michoacan in western Mexico all the way down to northwestern Costa Rica, with isolated pockets found on the Atlantic Slope in central Veracruz and the Sula Valley in Honduras, several distinct subspecies are found. For instance, I just spent three months in central Veracruz, where the nominate form is relatively small and the rufous is really restricted to the nape - hence the name, Rufous-naped Wren.

But take a closer look at this bird. I photographed it today in the Botanical Garden of San Salvador, in El Salvador. It is much bigger than the nominate form found in Veracruz, and the rufous coloration extends all the way down the back. The nominate form has spots on the belly, while the belly on this bird is unspotted. This particular subspecies, capistratus, is further characterized by some dark and whitish bars and streaks on the back, and by a distinctly barred tail. These latter two field marks are not shared by nigricaudatus, a subspecies found in Chiapas and western Guatemala that otherwise resembles it.

In the Botanical Garden, these birds were common and easily observed. Adaptable and versatile, a small population around the garden's restaurant appeared to have specialized in feeding on lunch leftovers. Wrens were obviously keeping a close watch on how people were progressing with their lunches, and as soon as a party left, leaving behind a table with nearly empty plates, the wrens moved in and cleaned those plates of whatever was left. Each time, they had only a minute or less of available feeding time, before the restaurant's cook would come out and clean the tables.

Numerous also in the garden were iguanas, like this older, large individual.

Friday, November 20, 2009

Veracruz season over

The 2009 hawk count season in Cardel and Chichicaxtle, Veracruz ended today with a last group of 34 Turkey Vultures in Cardel, for a day total of 341 raptors counted in Cardel. For the season, we counted more than 4.5 million birds this year, which sounds like a lot but is actually about average for the two sites. The bird pictured above is a wintering resident in Chichicaxtle, a Merlin.

This weekend, some of us counters will go birding and rafting in the Jalcomulco area here in Veracruz.

Then on Monday, Kashmir and myself will head south to first stop San Salvador, where we will start the Golden-cheeked Warbler field season 2009/2010 proper. This will take us to Costa Rica and Honduras.

Monday, November 16, 2009

Black-throated Green Warbler

Today a picture of a Black-throated Green Warbler, taken last week in Parque Natura in Xalapa, where this species is an abundant winter resident. This bird is an adult male, as evidenced by the entirely black throat and breast, heavily veiled with thin white tips. The thin white feather tips are part of the fresh fall plumage of adult males, and wear off in the course of the winter, when the entire throat and breast turn a solid black. The bill, here with some brown along the gape, will also turn completely black during winter. Immatures show more brown on the bill.

This species is of course far more common than its sister species, the Golden-cheeked Warbler, which I will be looking for in Central America once again this winter. My field crew will be visiting Honduras and Costa Rica in search of them. Costa Rica is really outside the known wintering range for this species, yet records exist for that country. We will attempt to describe 25 mixed warbler flocks in Costa Rica, in hopes of encountering maybe a few goldencheeks if we're lucky. We will be seeing far more Black-throated Green Warblers, a common winter resident there also. The adult males of both species are distinctive and easily separated. At the other end of the plumage spectrum, immatures of these two species - especially immature females - are quite similar. When given good views, even these plumages are separable in the field, for the upperside of even the drabbest goldencheek will still be darker than that of any black-throated green, while the auricular patch on the latter species is never present on a goldencheek. The eye line of goldencheeks is always more pronounced than on black-throated greens. The vent of any goldencheek is pure white, while black-throated green always shows a yellow wash in that area, fainter in some individuals. With care, they can be separated.

It's possible that some Costa Rican records of Golden-cheeked Warbler pertain to misidentified Black-throated Green Warblers, and it's also possible that goldencheeks do winter in very small numbers in that country. I know we will be searching for a needle in a haystack, but that should make it all the more rewarding if we do find one, or some.

My visit to Parque Natura was not to look for Black-throated Green Warblers, but for the endemic Hooded Yellowthroat, said to occur there in open, brushy situations. Bob Straub's bird finding guide to Veracruz states that the species is more easily found there in spring and summer, when the males advertise territories. Still, I thought I'd give it a try, after having dipped on the Burrowing Owls the week before. This was another species I had never seen before. After many hours of searching I did eventually find a female, which came out of the brush briefly upon spishing, long enough for satisfying looks but not long enough for an actual photo. It was accompanied by a Wilson's Warbler, which was more cooperative.

Wednesday, November 11, 2009

Cardelia

The 'river of raptors' here in Veracruz has almost dried up, and on most days now amounts to little more than an occasionally pulsating rivulet. Various winter residents have arrived, among them a Merlin, a Cooper's Hawk and a few redtails in Chichicaxtle, and in Cardel an immature female Cooper's Hawk.

But Cardel's most famous avian winter resident is this bird, an adult female tundrius Peregrine that has wintered here for many years now, and is known to us counters as 'Cardelia'.

Cardelia arrived in the last week of September, and since then can often be found perched on one of the town's communication towers. She generally leaves Cardel's sizable pigeon population alone, and usually goes hunting in the dunes and on the beach nearby. Shorebirds and waterfowl are probably tastier than city pigeons.

Two of the three communication towers provide favorite perches, the third is barely used. When perched on one of these towers, she does not allow any raptor or vulture near or on it. Migrant Peregrines and resident Aplomado Falcons are often greeted by loud calling and are usually shown the way out.

She did allow a (smaller) male to sit with her for a few weeks, although he hasn't been seen lately. He was named, rather unimaginatively, 'Cardelio', the boyfriend of Cardelia.

For a short while early October, there were even three Peregrines in Cardel. At the peak of migration, there was probably enough food around in the form of migrant shorebirds to support three Peregrines. It seems likely that Cardelio and the other, unnamed suitor - also a male - were eventually chased out of town as the local food supply shrank.

Sunday, November 8, 2009

Nemesis bird

Every birder has a nemesis bird. Mine evidently is Burrowing Owl.

Yesterday on my day off I traveled all the way to Perote, near the state line with Puebla, just to see this bird. A few of them supposedly could be found near a Coca Cola factory just outside Perote, a mid-sized town on a plain at 2,400 m altitude. I searched for several hours but came up empty-handed, just like a few years ago in Florida, when two confirmed locations appeared owl-free during my visit.

I did see many other birds that are typical of this area, part of the Central Volcanic Belt here in Mexico, which you can't see in the coastal lowlands of central Veracruz. None of these birds were lifers, but it was cool to see them. The only thing I didn't like about them was that they weren't Burrowing Owls. Here are some Clay-colored Sparrows. Another abundant sparrow species there was Vesper.

These two birds on the same cactus are Curve-billed Thrasher (left) and Canyon Towhee, both common at this site.

Also abundant there was Loggerhead Shrike, Horned Lark, American Pipit, and Say's Phoebe. Waiting for the bus back into town, and feeling disappointed for having dipped on the owls, I saw a small group of European Starlings. Ten minutes later I saw another one. Starlings are very recent arrivals in the state of Veracruz. Versatile generalists, they are still expanding their range southward.

Wednesday, November 4, 2009

Interesting sightings

As I wrote in the previous post, the days with the big numbers are over. But late season in Veracruz is always good for a few surprises. A fitting Halloween surprise was a mid afternoon high flyover Barn Owl in Cardel on the 31th of October, while yesterday these four Snow Geese made for some excitement on an otherwise dull gray November day. This species does winter in the northern part of the state of Veracruz, but is rare in Central Veracruz. I didn't see it last year, and several of the local counters have never seen a Snow Goose. The birds circled for a while between the Chichicaxtle and Cardel count sites, perhaps trying to fit in with soaring American White Pelicans.