Thursday, May 19, 2011

Piping Plover - Charadrius melodus

This is a brief tail (pun intended) of a bird that is in need of a fighting chance of species survival. The Piping Plover is endangered, i.e., threatened to disappear from regions in which it lives and breeds.


 Populations of the Piping Plover (Charadrius melodus) have declined alarmingly in North America in recent decades, enough to be placed in the "endangered" or "at risk" category in most of its historical breeding regions -- the Great Lakes region (where no successful nest has been recorded for over 20 years), sections of the Atlantic coast from the Maritimes to Virginia, and the Northern Great Plains (which has the largest population, consisting of about 1,400 breeding pairs). In Canada it is nationally endangered and hence protected by the federal Species at Risk Act since 1985 and protected also under the federal Migratory Birds Convention Act. It is also protected by provincial endangered species legislation in all provinces in which it breeds, including Alberta.


In Alberta, and elsewhere too, the Piping Plover is a bad news story, but the story has begun to improve. Between 1986 and 2001 census results (yes, birds too, at least some, are required to say tweet!) indicated a 50% population decline, the Alberta Conservation Association (ACA) reports. According to the ACA, "research ... annually over the past 20 years ... has shown very clearly that predation of eggs is one of the biggest problems for the Great Plains/prairie population, limiting its recovery. Although few people have actually witnessed predation of plover eggs, through their research, field biologists know that the main egg predators are crows, gulls and mammals such as raccoons, fox, coyote and skunks." Isn't that a stretch? -- one might think. These predators have always been around. True, but recreational use of beaches and other human encroachments and the detritus humans leave behind have increased populations of gulls, crows, foxes and skunks in some areas where these plovers breed. There are other factors that inhibit the plover's breeding success -- nicely described at http://www.abheritage.ca/abnature/speciesatrisk/plover_limits.htm.


Though by no means out of the woods (or salt flats) yet, the story is heading in a happier direction in recent years. Again, according to the ACA: "Since 2001, the Alberta piping plover population has increased by over 95 percent, from 150 adults to the 295 adults counted in 2008!" This is due to several recovery measures, most importantly perhaps, protecting as many nests as possible with predator exclosures. These exclosures are round mesh cages that allow the piping plovers to enter the nest but exclude their predators that like plover eggs. The incubating plover simply runs between the holes in the mesh of the exclosure and is then protected from most predators.

Enough on the plight of the plovers. Now to these lovely little creatures themselves.


It is a fairly stocky little (about the size of a large sparrow) member of the plover family (Charadriidae) that belongs to the Shorebird order (Charadriiformes). Its most distinguishing visible field marks are a black head stripe that goes from one eye to the other, a single black band across its neck, a long white eyebrow, a bill with bright orange base and black tip, orange legs. In the photo below, a male-female pair, you may spot the differences between male (right) and female (left): look at the thickness of the necklace and the colour of the beak.

Female (left) and Male (right) pair: spot the differences!

Frontal view of the male's head and neck band
Its habitat requires wide sandy or gravely shores of lakes or large river sandbars. In Alberta and elsewhere on the prairies it is typically found on the "salt-flat" shores of shallow, saline lakes. It needs a wide swath of vegetation-free or sparsely vegetated beach where it scrapes out its nest in the sand or gravel. Nests are often lined with small pebbles or shell remnants to keep the eggs off the wet sand and to provide camouflage. Below is a typical salt lake in Alberta (name and location undisclosed) that the Piping Plover looks for, and an image that shows how well this little creature blends into the salt-covered gravel.

Saline lake in eastern Alberta






Why "Piping" Plover? I used to think it had to do with the "piping" that encircles its neck, the neck band. Not so, actually. The Latin species name melodus for once gives the clue. The name refers to its distinctive whistles that are often heard before the bird is seen.


If you happen to see a Piping Plover, count yourself lucky to meet this rare bird. Give it lots of room to feed and tend its nest or young chicks -- who, by the way, emerge fully feathered from the eggs in early June,  begin to run a few hours after hatching, and feed themselves on small insects found on the surface of the sand found at shorelines. The adults provide protective cover for the chicks until they can fly, about 20 to 25 days after hatching.


Friday, May 13, 2011

Blackbirds in the cattail marshes


The wetlands with cattail growths come to noisy life in late April and early May. The male blackbirds are back, often three kinds in the same marsh, competing with each other for prime nesting territory.  The three blackbirds mentioned here all belong to the Icteridae  (a Latinized derivation from the Greek ikteros, "jaundiced one," on account of yellow as a prominent plumage colour in many, but by no means all of the Icterids) that includes all varieties of New World Blackbirds and Orioles, as well as the Meadowlarks, and the Bobolink, close to a hundred species in all. This is one of the oddities of taxonomic classification: Icterids = Blackbirds. Not all black birds are Icterids and not all Icterids are black -- nor jaundiced, for that matter. Going up one level in the taxonomic pyramid, the Icteridae are a family that belongs to the order Passeriformes, Songbirds. Yet many of the Blackbirds, the three species mentioned below, for example, can't carry a tune to save their wings.

The Icterids are found only in the Americas. In Alberta, their early arrival and their throaty, growling "song" are happy indications of the return of spring.
The boldly coloured Red-winged Blackbird (Agelaius phoeniceusis the most familiar sight atop cattails. Glossy-black males have scarlet and yellow shoulder patches they can puff up or hide depending on how puffed up they feel. Its Latin name is derived from the Greek terms agelaios ("belonging to the flock") and phoinkeos ("purple-red" or "crimson," i.e., deep red). The history of the classification of this bird is interesting. Linnaeus, the 18th-century father of scientific classification of species, called it Oriolus phoeniceus, identifying it in relation to a another species. Later it was moved to the Agelaius family, an identification based on its behavioural trait of living in flocks.


Females are a subdued, streaky brown, almost like a large, dark sparrow.
  
Male Red-winged Blackbirds are not shy; they do everything they can to get noticed, sitting on high perches and belting out their honk-a-ree song all day long. "Song" is overstating it. Though not unpleasant to the human ear, their song is remarkable more for its volume than for its tonal beauty. They are aggressive defenders of their territories during the breeding season, spending more than a quarter of daylight hours in territory defense. He chases other males out of the territory and attacks nest predators.


Females are more subdued, staying low, and skulking through vegetation for food and quietly weaving together their nests and later feeding their young.

The Red-winged Blackbird is a highly polygynous species, meaning males have many female mates – up to 15 in some cases. But research has shown that the territorial male may not be able to prevent his females from hanky-panky with other males: according to the Cornell Lab of Ornithology up to a half of nestlings turn out to have been sired by someone other than the territory holder.



The Yellow-headed Blackbird is a startling, conspicuous, and quite beautiful breeding bird in many prairie deep-water wetlands with cattail or rushes. Its name, Xanthocephalus, means “yellow head,” a remark on the male’s striking saffron-yellow head, neck, and breast that contrasts sharply with the black plumage on the rest its body – except for a white wing patch that is visible in flight.


Females and young males are duller in plumage: bodies dull black and brown, with pale yellow primarily on breast and throat. 


The YHB is classified among the songbirds, but frankly, this must be an embarrassment even in the bird world. Its song, if you can call it that, is a hoarse, scratchy buzzing noise. Imagine the sound of an opening barn door that sits on very rusty hinges and you come close to the noise of the Yellow-headed Blackbird. Not really pleasant to the human ear, but amusing nonetheless. What counts is that it is pleasant to the ears of female YHBs – or, possibly, threatening to other males and other intruders.


Highly social, these large-bodied blackbirds breed in loose colonies that consist of grouped territories. The male defends a small territory of prime nesting reeds. Like the Red-winged Blackbird, this species too is polygynous – each male attracts up to eight females to nest within his area. Males arrive first at breeding locations and compete with each other for prime real estate before the females arrive. When the girls do show up, they select nest sites within a male’s territory. Nests are constructed by the female. The are always placed over open water and consist of a cup woven of strips of reeds, attached to reed stalks.


 

The YHBs clearly are the rulers of the cattails. They often, but not always, nest in the same marsh as the Red-winged Blackbird and the Common Grackles. The larger Yellow-headed Blackbird is dominant to the Red-winged Blackbird and displaces the smaller blackbird from the prime nesting spots. The Yellow-headed Blackbird is also aggressive toward Marsh Wrens, probably because the Wrens’ habit of destroying the Blackbird’s eggs. Among the entertainments that some cattail marshes offer is the shouting matches between Blackbirds and Marsh Wrens.


In my area, central Alberta, another blackbird that is often found in the same cattail marshes as the RWB and YHB is the Common Grackle, the largest of the three species mentioned here. Its scientific taxonomic name is Quiscalus quiscula. Both names (first = genus, second = species) are puzzling because they derive from the Latin word for quail, even though there is nothing quail-like about the Grackle. I have been trying to find an explanation for this but have not found one so far. Why Grackle as the common name? This comes from the Latin graculus, a term that is used to refer to Old World birds that are closely related to our crows -- jackdaws and choughs, for example. The Grackle does have some faint crow-like features, such as the size of its beak, its overall size, and its habit of rooting for grubs and other food items in lawns and fields. For these reasons in some areas folks refer to it as the Crow Blackbird.


In contrast to the other two, the Grackle not only gets little respect, but has historically been despised as a “maize thief” and general destroyers of crops. Here is how J. J. Audubon (The Birds of America, 1840-1844) describes  “their nefarious propensities,” as the popular sentiment of early 19th-century farmers had it: “Look at them: The male, as if full of delight at the sight of the havoc which he has already committed on the tender, juicy, unripe corn on which he stands, has swelled his throat, and is calling in exultation to his companions to come and assist him in demolishing it. The female has fed herself, and is about to fly off with a well-loaded bill to her hungry and expectant brood.”

During the breeding season the birds are stunningly gorgeous; they sparkle with rainbow-like iridescence, the hues changing as the angle of light changes. There are actually two forms of the Common Grackle, the purple Grackle and the bronzed Grackle. The first is found in the southeastern US, the second everywhere else, including in my region. Notice its bronzed body, especially in the first picture above.


Grackles live in flocks and are not as habitat-restricted as the other Blackbirds, both for nesting and food, but in some places they inhabit the same marshes as the other two blackbirds. They are virtually omnivorous.

This too is a songbird by taxonomic classification only, not because of the tonal quality of its vocalization. Pete Dunne, a renowned American bird expert, has it about right: "Noisy! Song is loud and harsh -- a gutteral protest followed by a breathy, strangled screech."
So, Songbirds they all are, songster, they are not! They are noisy, conspicuous denizens of our wetlands. They come early to announce the end of our long winters. I love them and look forward to their arrival. In fact, this year I was so eager for winter to end that I drove out to the local cattail marshes regularly from early April on, hoping to be there when the first of the Blackbird boys arrived.