Neotropic Cormorant

The Minnesota bird listservs have been buzzing about a possible Neotropic Cormorant in Minnesota.  This small cormorant is often recognized by the white band behind its bill, visible in this photo that Erika and I took this spring near Rockport, Texas. This species ranges throughout South and Middle America, north to Texas, Oklahoma, Arkansas, Louisiana, New Mexico and Arizona. It wanders further north, even to Saskatchewan and Pennsylvania. Neotropic Cormorants inhabit a variety of habitats and are tolerant of many human activities. They have, nevertheless, not been extensively studied by ornithologists (Telfair and Morrison 2005).

Sedge Wren

On Tuesday, Erika and I made a quick stop at the River Bend Nature Area near Faribault, Minnesota. We heard a Sedge Wren's familiar call coming from the swampy field next to the parking lot. A moment's spishing brought this curious wren up close. In July 2010, I blogged about a lot of Sedge Wren biology and included a link to the bird's call. Looking back at those earlier photos makes me chuckle over the improvement in my bird photography, the result in evolution of camera equipment rather than photographic skill. On our winter trip this year, I managed to fall on top of my camera. (I was chasing Green Jays). Even though Erika replaced my shattered lens, I do not recommend this as a strategy for updating equipment. A conundrum is that, with a larger lens, I tend to take photos of more distant birds. The results are not necessarily better photographs.

Plain Chachalaca

The Plain Chachalaca is found from the Lower Rio Grande Valley south through the lowlands of eastern Mexico into Central America. Despite their superficial resemblance to turkeys, chachalacas are more closely related to Australian megapodes. They are placed in the family Cracidae, which includes a number of other large gamebirds (guans and curassows). Unlike most other Gracidae, Plain Chachalacas prefer scrubland and forest edge rather than the deep forest. Thus these chachalacas are less prone to be threatened by tropical deforestation. Urban sprawl and large-scale agriculture, however, do threaten the species.

Chachalacas are named after their raucous dawn choruses. Erika and I found Plain Chachalacas in almost every refuge we visited in south Texas. The photo above was taken at the Laguna Atascosa National Wildlife Refuge. Most of the refuges in this region maintain bird-feeders, which make visits particularly rewarding for birders.

White-tipped Dove

Another south Texas specialty Erika and I found at Laguna Atascosa National Wildlife Refuge was the White-fronted Dove. Found across much of South America and Mexico, this dove is terrestrial. The species usually forages alone or in pairs and is is more often heard than seen.  This dove favors heavy vegetation, typically flying only short distances. Despite being a relatively common gamebird across its range, ornithologists know relatively little about White-fronted Dove biology (Hogan 1999). They are nonmigratory residents in Texas.

Palm Warbler

Although Palm Warblers are common migrants in our part of Minnesota, my only decent photograph was of the winter-plumaged bird in the first photo. I encountered that individual in downtown Key West in February 2011. (Palm Warblers were first found in Hispaniola, which accounts for their name.) Actually Palm Warblers breed in bogs and fens and enjoy one of the more northern breeding ranges of all warblers. Spring-plumaged birds are a whole lot brighter than those in winter plumage, as you can see in the next photographs. I banded this bird, my first for Minnesota, in Northfield on Friday. (I banded a few Palm Warblers in South Dakota, but never photographed one.)

Palm Warblers are recognized by their chestnut caps, yellow throats and under-tail coverts, and habitual tail bobbing. Two races are recognized and are fairly easily identifiable in the field. The Yellow Palm Warbler of eastern Canada and New England has completely yellow underparts. The Western Palm Warbler, which breeds west of Ottawa and uncommonly in Minnesota's Arrowhead, lack yellow across their mid-breasts.

The Western Palm Warbler is the race expected during migration in Minnesota and, as you can easily tell in my photographs, that is exactly what I banded in Northfield. Apparently the two races interbreed where their ranges meet. Wilson (1996) warns, however, that evidence for this intrebreeding is based on very few specimens and that "studies on the interactions of the two subspecies are needed."

Identifying the races of Palm Warblers may be more difficult than some books suggest. Chris Wood, of the Cornell Laboratory of Ornithology, writes "There is alarge amount of variation in both Western and Yellow Palm Warblers and the extent of yellow on the underparts is particularly variable in spring. A fair number of Western Palm Warblers are [extensively] yellow below. I would look more at the color of the nape and wings, which would be more strongly olive in Yellow Palm Warbler. The back of the auricular should be more yellowish, or at the very least a bit more olive. Yellow Palms also should show... extensive chestnut streaking on the sides of the breast ..."

Name that Duck!

Erika says that someone ought to write a field guide to Dabbling Ducks dabbling.  For these birds, if you guessed Blue-winged Teal, you would be correct.  These are prairie-breeding ducks. Populations depend on prairie pothole conditions, with low cycles corresponding with drought and wetland drainage. Blue-winged Teal also suffer very high predation rates--often over 90% of nests fail--by raccoons, fox, and coyotes. Nevertheless, since hitting a 40-year low in 1990, Blue-winged Teal numbers more than doubled (Rohwer et al. 2002).

Although males do not help with incubation or care of the young, in the spring they vigorously defend territories picked by the females. In the summer, males molt earlier than the females, and afterward head south without their mates and, by mid-August, arrive at their Gulf Coast wintering areas. This pair of Blue-winged Teal fed in a small pond near the Old Highway 77 Bridge in the Minnesota Valley National Wildlife Refuge near Minneapolis. I was surprised by the male's iridescent purple head coloration.

Green-winged Teal

Green-winged Teal are common, small dabbling ducks. Being a dabbler, they feed by tipping their bottons into the air in shallow waters on invertebrates and grass and sedge seeds. Unlike diving ducks that must run along the water surface, dabblers can take to the air in a single bound. Green-winged Teal differ from other dabblers in that they are one of the few that do not primarily breed in the prairie pothole region of north-central North America. Instead most breed in northern Canada and Alaska. Due to the remoteness of the breeding areas, Green-winged Teal numbers are high, and may be increasing (Johnson 1995). This teal is monogamous during the breeding season, although males will attempt extra-pair copulations. I photographed this handsome drake in late April at the Old Highway 77 Bridge in the Minnesota River Valley National Wildlife Refuge.

Green Jay

The suite of Texas bird specialties we found at Laguna Atascosa National Wildlife Refuge surprised me. I thought you had to be right on the Rio Grande to see them. The first of these birds was the Green Jay, found just north of the Rio Grande south through South America to Peru and Bolivia. As I ran about in chasing jays, Erika took these photographs.

South Texas Green Jay flocks contain related nonbreeding birds. Flocks contain a breeding pair, the current year's young, and jays from the previous year. What is unusual is that these nonbreeders do not help at the nests, as do many other birds. They do, however, provide territorial defense for the breeding pair. The birds from the previous year are run out of the flock when the current year's nestlings fledge. Oddly, Green Jays in Colombia do help their parents raise the current year's young. This difference may be the result of less abundant food resources in Colombia (Gayou 1995).

Tree Swallow

Tree Swallows are lovely, early migrants to Minnesota. I have previously blogged on this swallows on 20 April 2011 and 11 August 2011. Because they compete with Eastern Bluebirds for nesting holes, the swallows are sometimes maligned by bluebird enthusiasts. If you favor bluebirds over Tree Swallows, you have a number of options. Keep your bluebird boxes widely separated. Bluebirds defend larger territories than do swallows. Too many boxes increase swallow/bluebird aggressive encounters. Bluebirds often are the victors when there are not too many swallows in bluebirds' habitat.

Surprisingly another solution is to pair bluebird houses. Swallows will drive out close-by swallows, but they often ignore nearby bluebirds. Even back-to-back boxes will work. Nevertheless, the houses for bluebirds should still be widely (300 feet) separated. These bluebird facts are from Chris Gates and his website that makes for interesting reading. This year my friend Penny has been having a great time running a bluebird trail--check out her website.

Greater Roadrunner

Erika picked the next stop of our road-trip, the Laguna Atascosa National Wildlife Refuge northeast of Harlingen, Texas. I knew little about this refuge except that Aplomado Falcons have been released there in an attempt to reestablish them in the United States. I was not expecting the diversity of species we found near the refuge headquarters. The first hint of this entertaining birding was our welcome by a pair of roadrunners at the refuge gate.

I have previously posted on roadrunners, terrestrial cuckoos found across the southwestern United States, from coast to coast (and south into central Mexico). Greater Roadrunners are monogamous, maintain long-term pair bonds, and mutually defend territories. Every spring pairs renew their bond through elaborate courtship desplays involving a lot of male dancing, including his bringing nesting material and food items to his mate (Hughes 2011),

As seen in the bottom photo, adults have prominent erectile crests and dark blue skin around their eyes. The orange postorbital apteria (the skin between the feather tracts) is usually not visible.