A very clever namesake

Cauchy, below, has the same name as an eminent French mathematician, and several concepts and theorems, particularly in infinitesimal calculus and complex analysis.

Cauchy and Bevo the bull

This particular Cauchy is still learning some rather basic concepts, but he is adept at attacking his beloved bull, Bevo.

How to become an endangered species

2015 update: I did some experiments and found that little bee-eaters, African hosts of another deadly brood parasitic bird, are also remarkably maladapted when it comes to avoiding parasitism.

I recently made a pilgrimage to see a very special bird, the Kirtland's warbler (Setophaga kirtlandii), one of the rarest and most endangered wood warblers. 

Male Kirtland's warbler in all his breeding glory

This wee creature has decidedly unfortunate tastes in where to breed. It is both fussy and unaesthetic, nesting only in the scrubbiest, shabbiest stands of young jack pines (Pinus banksiana) that grow in vast stands on sandy soil in northern Michigan. The success of Smokey Bear, the US Forest Service's campaign to stop wildfires, allowed all the jack pines to grow big and strong, leaving almost no young trees for the warblers to nest amongst. 

Cowbird egg (the big one) in a Kirtland's warbler nest

To make matters worse, human development has greatly expanded the range of the brown-headed cowbird (Molothrus ater), a brood parasite that lays its eggs in the nests of other species, thereby dispensing with the bother of incubation and childcare. The Kirtland's warbler was not historically exposed to cowbirds -- named for their habit of following bison (and subsequently cows) to eat insects disturbed by the moving herds. Without having evolved in tandem with the cowbirds, Kirkland's warblers are hopeless when faced with a cowbird egg in the nest. Instead of tossing the foreign egg or chick out, these tiny birds proceed to care for their parasitic offspring, which grabs all the food and starves its smaller warbler foster siblings to death. By the time they are fully grown, cowbirds are 3-5 times heavier than their foster parents.

Courting cowbirds

With habitat loss and intense parasitism by cowbirds, the Kirtland's warbler almost went extinct about 50 years ago. However, it has since become one of the best conservation successes in America. The U.S. Department of Agriculture Forest Service and the Michigan Department of Natural Resources began logging jack pines to simulate the disturbance caused by wildfires, and to produce large enough (at least 160 acres) areas of short young jack pine to suite the Kirtland's warblers. In addition, they trapped and killed thousands of cowbirds. As a result of these ongoing efforts, the Kirtland's warbler has now expanded its breeding range to bits of Wisconsin and Ontario.

The Kirtland's warbler is now the subject of considerable local attention, partly because it is an eco-tourist (or at least mad birder) attraction. There is a Warbler's Way Inn, and until recently, a Kirtland's warbler festival. The jack pine habitat is protected, so one is forced to join a tour to see birds. That said the tour was excellent, and well worth waking up at 2am and driving for 3 hours to see several male Kirtland's singing with gusto.

For more information:

Michigan Department of Natural Resources

University of Michigan, Museum of Zoology

Troglodytidae

Wrens are one of the only bird families I can think of that are more spectacular and widespread in the New World, while also being present in the Old World. In addition to their unusual biogeography, wrens are highly diverse in appearance and behavior. 

Troglodytes troglodytes, Greek for cave-dweller, is the only Old World representative. This diminuitive species is highly polygynous, which means that each male has several mates, each of which he attracts by building wee nests in some nook or cranny of a rock, building or bush.

Eurasian wren (Troglodytes troglodytes)

In striking contrast, the giant wren, endemic to Chiapas, Mexico, is about twice as long and five times as heavy as the dumpy little wren of European legend and literature.

Giant Wren (Campylorhynchus chiapensis)

Another endemic to Mexico, though with a less restricted range, is the felicitously named happy wren. 

Happy Wren (Thryothorus felix)

Inca Wren (Thryothorus eisenmanni)

Other wrens are aptly named for the places to which they are endemic. The Inca wren is only found around Machu Picchu, while the snail-eating Zapata wren only occurs in Cuba's Zapata Swamp. 

Zapata wren (Ferminia cerverai)

 



Wrens are also known for their varied and surprisingly loud songs. The musician wren of Amazonia is the subject of legend, including one in which all other birds stop to hear it sing.

Musician wren (Cyphorhinus arada)

Two of my favourite North American wrens are named for their habitat:

Marsh wren (Cistothorus palustris)

Canyon wren (Catherpes mexicanus)

Almost Cain and Abel

Some quick sketches from watching this enchanting webcam: Cornell Herons

Harassed parent scratching chin

Is this a crack I see before me?

Eggs about to hatch

Great Blue Herons (Ardea herodias) nest in rookeries, and lay 2-6 eggs. Parents share incubation duties, with males taking the day shift, and females the night shift.

Unlike many other birds, herons and egrets (and birds of prey) start incubating the moment the first egg has been laid, resulting in a large firstborn, and a succession of increasingly puny chicks, as each hatchling has to compete with its older, heftier siblings. Some heron chicks are more equal than others.

Goneril and Regan

While great egret (Casmerodius albus) chicks actively stab their siblings to death, great blue herons may simply starve their younger siblings by outcompeting them when food is scarce. This raises the question of why herons and egrets evolved to have more offspring than they can reliably support. One idea is that by creating an age and size disparity in offspring, parents can allow for environmental unpredictability at minimal cost. If times are good, then all the chicks survive, and if times are hard, the runts perish, but being the youngest, they've had the least invested in them anyway.

 

 

Spotted hyenas also appear to be siblicidal, which could explain why females have evolved bizzare mimetic penises that make childbirth a nightmare -- but that's another story.

For an excellent account of familial conflict, I highly recommend "More than Kin and Less Than Kind" by Douglas Mock.

Other sources:

National Audubon Society

Cornell "All About Birds"