From Silent Spring to Silent Night: A Tale of Toads and Men

As the semester winds down here at Fresno State, the Tri Beta Biology Club has a couple more special treats for us. For this week's Biology Colloquium, we bring you a real role model in Dr. Tyrone Hayes, an African American field biologist (yes, they exist, despite the stereotype) who became one of the youngest Full Professors at the University of California Berkeley. He will share his groundbreaking (and corporation-shaking) research on the effects of the herbicide Atrazine on amphibians, a taxon that has been in global decline for some time now, with pesticides hammering some of the nails in their collective coffin. Here's an excerpt about Dr. Hayes' work from the PBS documentary Frogs: The Thin Green Line:

And if that isn't enough to grab your interest, this might:

Here are details of the colloquium:

Tri Beta Biology Club presents:

FROM SILENT SPRING TO SILENT NIGHT: A TALE OF TOADS AND MEN

Dr. Tyrone Hayes

Professor of Integrative Biology

University of Californa, Berkeley

on Friday, May 6, 2011

at 3:00 PM in AG 109 (download maps here)

The herbicide, atrazine, is a potent endocrine disruptor. My laboratory’s studies in amphibians have shown that atrazine both demasculinizes and feminizes exposed males at levels as low as 0.1 ppb. Our previous worked examined morphological effects, including the loss of androgen-dependent sexually dimorphic features, and the development of estrogen-dependent features in exposed males. These findings are consistent with an induction of aromatase, resulting in decreased androgen secretion and inappropriate estrogen synthesis and secretion. Our ongoing studies focus on behavioral effects in male frogs exposed throughout life and demonstrate both the loss of male reproductive behavior and the induction of female-typical behavior in exposed males. These data on amphibians and the proposed mechanism are consistent with findings across vertebrate classes, including humans, and raise concern about the role of this common environmental contaminant in reproductive hormone-dependent cancers and declining fertility in humans.

Call the Biology department (559•278•2001) for more information. You can also download the flyer here.

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Where in the world is the Yellow-billed Magpie? Help us find out this weekend!

See and download the full gallery on posterous

What a handsome corvid, the Yellow-billed Magpie. How curiously restricted, its global range:

 

This lovely bird is another one I consider myself fortunate to have seen up close (e.g., when I took the above pictures in Pinnacles National Monument recently), given that it is one of those rare endemic species found only in a particular small corner of the world. This one, as you can see in the above map (from the Birds of North America account for the species), happens to be restricted to parts of Central California, west of the Sierra Nevada mountains, along the San Joaquin Valley all the way west to the Pacific coast. You can find a more dynamic, birder-generated current map of sightings via eBird.

The distribution range has shrunk historically with humans taking over much of its habitat for farms and suburbia, but numbers may have been relatively stable until the turn of this millennium. It has remained a species of concern given its limited range, and how much we humans covet its habitat. Nevertheless, the bird appears resourceful enough to have adapted to living amid human enterprise in some of the world's richest farmland in the valley and the sprawl of the San Francisco Bay Areas! Must be those clever corvid genes that have made the bird flexible enough to deal with some of the insults from us.

Our insults have run quite the gamut, including direct loss of habitat, concerted poisoning and bounty hunting campaigns because the bird is thought to be an agricultural pest (especially for the fruit/nut crops common around here, I think), and most recently, the arrival of West Nile Virus (WNV) in California. That last has landed the Magpie on Audubon's watchlist, for it has turned out to be perhaps the most susceptible to the virus. The population may be declining in recent years - but we don't really know what its status is with any certainty! Remarkable that, given how many excellent biologists live and work in and around the species' range at some of the world's top universities!

And I include myself among the ornithologists in the region who would like to keep a closer eye on this species. When I arrived in Fresno, West Nile Virus had just hit the state, and I grew curious about the range of the Yellow-billed Magpie because it wasn't to be found in or around Fresno! The distribution map intrigued me when I first found it because the bird is reasonably abundant in suburban / rural / farmland habitats north of Fresno county all the way up to Sacramento; and along the coast range to the west its range extends farther to the south as well. Yet, for some reason, it wasn't to be found in Fresno, even in habitat that I would be hard pressed to tell apart from areas 50-100 km north of us where the species is common! I haven't found a satisfactory explanation for this gap in its distribution, for I'm sure it used to be here, but not any more. Some oldtime bird/wildlife watchers in Fresno have hinted that the species was actively exterminated from the county because of a bounty on its pretty head several decades ago when it was considered a pest! That might explain its disappearance, but its not clear why it hasn't come back. Is it still being hunted/poisoned by farmers? Or has the habitat been altered enough to deter recolonization, presuming northern populations are productive enough (which they may not be). I suspect there is enough in those questions for a potential masters thesis, but haven't managed to find a student sufficiently motivated to go chase them. Know any?

Meanwhile, recent studies at UC Davis have focused on modeling habitat needs, on the effects of WNV on the birds, and on loss of genetic diversity through inbreeding. Those studies (follow the link for more info) have drawn upon help from citizen scientists who can report sightings of live and dead birds, the latter being collected for WNV screening. Visit Magpiemonitor.org for more on participation and results.

Right now, we all get a chance to help more broadly as well, by participating in a survey this weekend, organized by California Audubon and eBird. Here's the invitation:

Yellow-billed Magpie survey set for June 4-7, 2010

If we want to help the Yellow-billed Magpie survive, we need to know where it is living and in what numbers. And that’s where you can help. Audubon California is sponsoring a four-day statewide survey of Yellow-billed Magpies enlisted the help of volunteer birders.

Taking part is simple: All you need to do is log into eBird and record your observations.

Shortly after the survey, we’ll tally up the results and every participant will receive a report of the findings. Audubon California will use these findings to guide our conservation efforts for this bird.

Click on the links to the left to learn more and to take part in this important volunteer project.

via ca.audubon.org

I hope you can participate in the survey on what promises to be a nice weekend for birdwatching in the valley. At least, if you are out and about anywhere in this species range this weekend, I hope you will keep en eye out for this not inconspicuous bird and report any sightings.

Happy Magpie tracking!

Reference:

Reynolds, M. (1995). Yellow-billed Magpie (Pica nuttalli) The Birds of North America Online DOI: 10.2173/bna.180

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Alaotra Grebe: another one (that we know of) bit the dust...

London, England (CNN) -- The Alaotra Grebe, a small diving bird native to Madagascar has been officially classified extinct, according to a leading bird conservation organization.

BirdLife International reported that the species, once found on Lake Alaotra, the largest lake in Madagascar, declined rapidly due to carnivorous fish being introduced to the lake and the use of nylon gill nets by local fishermen.

"No hope now remains for this species. It is another example of how human actions can have unforeseen consequences," Dr Leon Bennun, BirdLife International's director of science, policy and information said in a statement.

via cnn.com

And so the bad news continues as we march on, oblivious, right through this Holocene mass extinction, uncaring, unaware of, or unwilling to admit our own culpability. Read the rest of the CNN story and Birdlife's report for more bad news about species on the brink. That we know of.

Posted via web from a leaf warbler's gleanings