Archive for the 'Fieldnotes' Category

Elegy for Martha

One hundred years ago today, Martha died of old age in Cincinnati. She was 29 years old and had been raised since birth in captivity. She never reproduced.the_passenger_pigeonMartha was the last of her species, the Passenger Pigeons (Ectopistes migratorius). Of course, by the time of her demise, the species was already functionally extinct in the wild. She was the coda, the famous last one perching. From billions to one to none in a century. Just thirty years previously, hunters were killing 50,000 Passenger Pigeons a day at one of the last big breeding sites, in Michigan. And further back, in 1813 Kentucky, J.J. Audubon and company famously saw them darken the sky for three days running. There were more Passenger Pigeons, it has been estimated, then there are now birds of all migratory species in North America. passenger_pigeon_slaughter 1884But isn’t there something wrong with those numbers? They don’t seem right: how could that kind of population be sustained? It probably couldn’t have, and may very well have been a result of the radical transformation of the colonial American landscape in the first place. European settlers quickly reduced the pigeon’s competitors — mice, squirrel, turkey, deer, etc., and of course the local humans — for mast — acorns, beechnuts, chestnuts, walnuts, etc. — setting the stage for an astonishing boom. The inevitable bust, however, was driven to extremity by a combination of forest clearance and unparalleled slaughter. The photo above is from late in the game, the late 1880s, after a slaughter for this cheap source of protein.

So when you remember this lonely caged pigeon today, think of the whole continent, the whole world, behind her. That’s what is gone.

Common Nighthawks

Chordeiles minorIt’s been a difficult week. But one of the highlights was on Thursday, when a friend and I went into Prospect Park in the late afternoon. Just before sunset, we were in the Nethermead. Overhead, the chittering of many Chimney Swifts was heard as the little birds darted all over the sky taking their last meals of the day. And then suddenly, nighthawks! Chordeiles minor are much larger than swifts, with long pointy wings and long tails, making them look somewhat falcon-like. But their fast, loopy, erratic flight is all their own. I counted seven at once, whirling through the air as they gobbled after insects in the aether. Another group of birders counted twice that many over time. These photos are mediocre, but hopefully hint at the setting sun’s under-lighting of the russety undersides of the birds, and their distinctive wing patch-stripes.Chordeiles minorThey are on the move now, to their wintering grounds in South America.

A quintessential summer evening bird, this is a species in decline. It’s one of the species mentioned in this excellent op-ed by the head of the Cornell Lab. A must-read.

Future Odes

Perithemis teneraEastern Amberwings (Perithemis tenera) in the reproductive wheel: the male holds the female by the back of the head; the female curves her abdomen up and forwards his genitalia, located (counterintuitively?) at the base of his abdomen. Pachydiplax longipennisA female Blue Dasher (Pachydiplax longipennis) dipping her abdomen down to lay fertilized eggs in a bit of water floating on a lily. Enallagma civileIn some species of Odonates, the male will continue to hold the female after mating and through the egg-laying process, precluding another male from mating with her, as with these Familiar Bluets (Enallagma civile). They can fly in tandem like this. Some species’ males will scoop out a previous male’s sperm from the female before adding his own with his specially equipped penis.Pachydiplax longipennisBlue Dasher females don’t seem to need chaperones. And look at all the eggs! Like pieces of short-grain rice, but much smaller. Of course, you know many will not make it to adulthood. These eggs were another post-photo discovery.

Bombus

BombusA bumblebee rumbles into the heart of the flower.

k10219Identifying bumblebees of the genus Bombus is not an easy task. In their new identification guide, Bumble Bees of North America, Williams, Thorp, Richardson, and Colla note that color patterns “can be strikingly variable within species and strongly convergent between.” As an example of the variability within a species: for the Yellow-banded (B. terricola) they show five queen bee patterns, five worker bee patterns, and seven male bee patterns; they also note its similarity to five other species. Oy! From my limited experience, I’d go with the bee systematist they quote: the genus is “morphologically monotonous.”

This guide uses color patterns, but also tongue length and cheek size to break down the forty-six species in North America north of Mexico. (Also used to differentiate these are male genitalia and genetic evidence, things even more remote from field observation.) Measuring a bee’s cheek isn’t something a lot of amateurs are going to do (and never mind the knees!). bombusMany of you are doubtlessly aware of the importance of honeybees as pollinators, and how their numbers have plummeted because of Colony Collapse Disorder. But bumble bees are also used commercially in pollination, especially in greenhouses, where their services are worth $10 billion annually. Unfortunately, the bumble bee pollination industry has spread bee diseases through their practices, introducing hazards to wild populations around the world. World-wide, bumblebee populations are mostly in a bad way, due to habitat loss, insecticides, climate change, pathogen spillover, and the introduction of exotic/invasive species. Systemic insecticides used to treat seeds are particularly insidious, as they remain present throughout the growing plant, including the pollen and nectar gathered as food by bees; if not immediately toxic, these poisons can disrupt foraging and colony development over time.

Since the beginning of this century, one North American species, the Franklin (B. franklini) has had such a rapid decline it is considered close to extinct; another, the Rusty-patched (B. afinis) is the only bee on the federal endangered species list.

bombus2

Among many things gleaned from this volume, I learned that Bombus diversity is greater in habitats with cooler temperatures and montane landscapes, unlike most other bees, who prefer warm dry, Mediterranean style habitat. The Polar B. polaris, for instance, is found across the far northern swath of the continent.

BTW:”Bumblebee” seems more English English; “bumble bee” more American English. bombusPhotos taken around Brooklyn in recent weeks. Join me next Wednesday at Brooklyn Bridge Park where we should see a few late afternoon bumblers. Also, could it possibly be that you aren’t subscribing to these posts yet?

Great Crested Flycatcher

Myiarchus crinitusAlways a nice surprise to get a good look at a Great Crested Flycatcher (Myiarchus crinitus), since they are usually at tree-top level. I thought this might be a migrant, and it may well be, but it should be noted that there are breeding records for the species in Prospect. They are the only cavity-nesting flycatcher in the U.S. The bright sun is making its neck look too white; the birds are more gray in the feather.

Orange Is the New Bluet

Enallagma signatumA male Orange Bluet (Enallagma signatum) in the afternoon sun.

Spotted (or Not) and Streaky

Actitis maculariusSpotted Sandpipers (Actitis macularius) — no spots once they’ve moved out of their breeding plumage — are patrolling the edges of fresh water bodies now during migration. Parkesia noveboracensisAlso along the watery edges these days are Northern Waterthrushes (Parkesia noveboracensis).


Share

Bookmark and Share

Join 295 other followers

Twitter

  • 6500 casino jobs disappearing in Atlantic City: the perils of a casino economy, will-o'-the-wisp development. 1 hour ago
Nature Blog Network

Archives


Follow

Get every new post delivered to your Inbox.

Join 295 other followers