Tuesday, February 12, 2013

WHAT'S WITH THE WHITE BIRDS?


We become so used to seeing birds such as robins and chickadees and sparrows that we notice right away when one of them is oddly colored. The abnormal color variations that are seen in birds often are the result of mutations that involve the reduction or lack of melanin pigments. When melanin is reduced, dark feathers become paler, even whitish. When melanin is absent, feathers are pure white.

Albinism involves a complete absence of melanin and usually results in a pure white bird with red eyes. The melanin pigment that gives birds brown eyes is absent, so the red blood is visible through the transparent cornea. This mutation does not affect other pigments, so if a bird has carotenoid pigments coloring it red or yellow, that color may remain.

Leucism is different from albinism in that it may affect all pigment types, reducing their concentration to produce a paler bird or eliminating them entirely to produce a white bird. This can occur in some or all feathers, making some birds a patchwork of normal and white or whitish feathers. A bird that is white with brown eyes is leucistic.

Odd variants are typically seen in the most common birds, so even when such a mutation is rare, we see enough individuals to eventually encounter a funny-looking one. Robins that were pale overall have been reported with some regularity. Dark-eyed Juncos are often reported with scattered white feathers, even a head pattern somewhat like a chickadee; pure white ones are much rarer, perhaps in part because they are very conspicuous to predators and don't last long! You can see why these mutations would remain rare.


Some populations of Black-capped Chickadees in the Seattle area have persistent leucistic genes, and individuals are seen year after year in a neighborhood with different combinations of whitish caps and backs and white outer tail feathers (looking a bit like a junco as they fly away). Apparently chickadees don't have enough visual predators to eliminate these genes entirely.







I know of at least four male Red-winged Blackbirds in Washington that had plumage almost identical to the one shown here. Apparently that leucistic mutation is widespread in the genome of this species, at least in the Pacific Northwest. Is this some basic blackbird color pattern that is suppressed by the males' black pigment?

Leucism can be hard to detect in birds such as gulls that are already gray and white, but a pure white one like this Ring-billed Gull usually indicates this mutation. Remember that egrets and swans aren't leucistic; they just evolved white plumage, obviously advantageous to them.

Dennis Paulson

Monday, February 4, 2013

Microplastic ingestion by seabirds: ongoing research at the Slater Museum

Plastic from a Northern Fulmar stomach 

Research on ingestion of microplastics by seabirds continues at the Slater Museum.  With the help of Shep Thorpe, VMD, we have examined additional Northern Fulmar stomachs from 2012 from the WA and OR coast.  These were recovered by Wildlife Center of the North Coast (WCNC), Sharnelle Fee director.  There was an additional bird from Ocean Shores, WA provided by Sheila McCartan, Nisqually NWR.  The Ocean Shores bird was remarkable in having 6.0 gm of plastic in the proventriculus and 1.04 gm in the ventriculus (pictured).  Some pieces were the size of guitar picks.  There was one nurdle (labeled) which is a premanufactured plastic pellet.  Typically fulmars have less than 1 gm.  The Ocean Shores bird probably had enough plastic to incapacitate it leading to its demise. 

Research continues to rely on collection of specimens by Sharnelle Fee, Wildlife Center of the North Coast and Shep Thorpe, DVM, for dissection and separation of stomach contents.  Shep expanded discovery to the intestines where he has discovered small particles of plastic, parasites and clues to causes of mortality.   

Professor Peter Hodum in Biology is directing the research with students Alicia Terepocki, Alan Brush and Olivia Feinstein.  All are presenting posters based on their research over the past year at the Pacific Seabird Conference in Portland this month.

Abstracts from the Pacific Seabird Group 40th Annual Meeting 20-24 February 2013 Portland

USE OF A DIVING PROCELLARIIFORM, THE SOOTY SHEARWATER, TO EXPAND A MARINE PLASTIC BIODINDICATOR NETWORK

Alexander Brush, Gary Shugart and Peter Hodum, Biology Dept & Slater Museum., University of Puget Sound, 1500 N. Warner, Tacoma, WA 98416 USA, ABrush@pugetsound.edu

There is growing recognition that plastic pollution in our oceans has reached a critical level and must be addressed. Seabirds, especially procellariiforms, have proven to be a useful bioindicator of marine plastic debris through the monitoring of their ingestion habits. To date, most efforts in documenting procellariiform ingestion of plastic have focused on primarily surface-foraging species. There is reason to suspect, however, that pursuit diving species may not reflect the same plastic ingestion patterns. In this study, we examined the stomach contents of Sooty Shearwaters (Puffinus griseus), a species that uses both surface seizing and pursuit diving to forage. We collected samples from 26 birds from the northern Oregon/southern Washington region to quantify the frequency of occurrence, abundance, color and size of plastics in the diet. Plastic was found in 69% (18 out of 26) of specimens, which is lower than incidences of plastics in Fulmar stomachs. The abundance, color and size of plastics found in the Shearwaters will also be presented. Due to the differing feeding habits in Shearwaters versus Fulmars, it was expected that plastic categorizations would produce different results in the two species for amounts and types of plastics found. If our hope is to create a comprehensive network of seabird bioindicators of plastic debris then our knowledge base must be expanded to species that reflect a wide variety of foraging guilds, as they are likely to provide unique insights into the marine plastic issue.

NOTHERN FULMARS (FULMARIS GLACIALIS) AS BIOINDICATORS OF ENDOCRINE DISRUPTING PLASTICIZERS IN THE MARINE SURFACE ENVIRONMENT
Olivia Feinstein*1, Erica Donnelly2, Hannah Nevins2 and Peter Hodum1,2, 1Biology Dept., University of Puget Sound, Tacoma, WA, 98416 USA, ofeinstein@pugetsounde.edu 2Oikonos Ecosystem Knowledge, Benicia, CA
Many phthalates used to synthesize plastics have been identified as endocrine disrupting chemicals (EDCs), with studies showing dramatic deleterious effects on a variety of species as a result of exposure to growing numbers of EDCs in the environment. The Northern Fulmar (Fulmarus glacialis) is an opportunistic seabird which inadvertently consumes plastics as it forages. Previous studies of Fulmars suggest that plastics are leaching EDCs into the bird’s systems. We determined the percentage of plastics ingested by fulmars that contain EDCs. A collaboration with the Long Marine Research Lab allowed for geographic comparisons of EDC concentration intensities along the West Coast. The percentage of plastics in the diet of fulmars that contained plasticizers was below 3% in all tested regions. Plastic proportions in Alaska differed significantly from those in California and Washington. Our analyses confirmed that fulmars are effective bio-indicators of plastics in surface marine environments and that the surface waters in tested regions are not highly contaminated by plastics containing EDCs. EDC-containing plastics typically displayed negative buoyancy and sank in seawater and may be accumulating in benthic regions. The impacts of plastic ingestion may be a more significant source of contaminant uptake by seabird species than previously assumed. Additionally, there are physical consequences to species; plastics take up volume in the stomach reducing digestive capacity which blocks nutrient absorption.

PLASTICS IN THE PACIFIC: REGIONAL COMPARISONS OF MARINE PLASTIC INGESTION BY NORTHERN FULMARS
Alicia Terepocki*1, Erica Donnelly2, Hannah Nevins2, Gary Shugart1 and Peter Hodum1,2, 1Biology Dept & Slater Museum., University of Puget Sound, Tacoma, WA, 98416 USA, aterepocki@pugetsounde.edu 2Oikonos Ecosystem Knowledge, Benicia, CA
Plastic pollution is increasingly recognized as an escalating threat to marine ecosystems. In the face of this developing issue, monitoring ocean-wide levels of pollution has become crucial. Successful monitoring programs utilizing Northern Fulmars (Fulmarus glacialis) as bioindicators of marine plastic pollution have been instituted in northern Europe and central California. As generalist and surface feeders, fulmars are an ideal indicator due to their susceptibility to ingesting plastic debris. In this study, we examined fulmars from northern Oregon and southern Washington (n=89) to determine the frequency of occurrence, abundance, size and color of plastic ingested and make inferences about the state of marine plastic pollution in the Pacific Northwest and feeding habits of fulmars. We compared these findings with those of birds from Alaska (n=46) and California (n=44) to obtain information on regional differences in plastic pollution in the northeastern Pacific. Results suggest marine plastic densities vary regionally, in all regions plastic ingestion was prevalent.
PSG’s 40th Annual Meeting:
February 20-24, 2013 at the Portland Hilton


*

Saturday, February 2, 2013

What the heck is a groundhog?

A Groundhog (Marmota monax)
Happy Groundhog Day, everyone! During this time of groundhog celebration, do you ever stop and wonder, "What in the world is a groundhog?"

We have all watched Punxsutawny Phil or Wiarton Willie emerge from his burrow to forecast the weather countless times, but where in the world did this tradition come from? And what is a groundhog in the first place?

Well, I am glad you asked, dear reader, for although these rotund rodents are national celebrities, most Groundhog Day revelers don't realize what a groundhog really is.

Groundhogs go by many names, other than "Phil" and "Willie" of course. Some call them whistle-pigs, land beavers, and, more commonly, woodchucks. But groundhogs do not have any immediate relations in the swine family (Suidae) and definitely aren't beavers. Rather, groundhogs are squirrels. Yes indeed, groundhogs (Marmota monax to be precise), and all other marmots for that matter, are the largest members of the squirrel family, Sciuridae.

An Olympic Marmot (Marmota olympus)
Here in the Northwest, we do not have groundhogs, but we have plenty of marmots, ground squirrels and gophers if you are searching for a woodchuck-related encounter.

What's the difference between these mammals, you ask?

Well, that depends on your definition of each critter.

Marmots are large Scuirids in the genus Marmota. In some regions, prairie dogs are also known as marmots, however these squirrels are in the genus Cynomys. Fun fact: the Olympic Marmot (Marmota olympus) is the only mammal uniquely endemic to Washington State.


A Mazama Pocket Gopher (Thomomys mazama)
Ground squirrels are a bit more difficult to define. In fact, recent phylogenetic revisions have split what was once a monogeneric clade (Spermophilus) into eight genera... In other words, nobody really agrees. And colloquial definitions vary as well. Typically, when one is referring to "ground squirrels," one could be referring to antelope squirrels (Ammospermophilus), typical ground squirrels (Urocitellus, Callospermophilus, and Ostospermophilus, all formerly in Spermophilus), prairie dogs (Cynomys), or even chipmunks (Tamias).

Gophers are equally difficult to define. Colloquially, gophers can include Scuirids, such as typical ground squirrels (as mentioned above) and prairie dogs, or it can include or members of the pocket gopher family, Geomyidae. The most common pocket gophers here in the Pacific Northwest are members of the genus Thomomys such as the Northern Pocket Gopher (T. talpoides) and the endemic Mazama Pocket Gopher (T. mazama).

A White-tailed Antelope Squirrel (Ammospermophilus leucurus)
Perhaps most confusing of all, is the fact that Groundhog Day has its origins with a different creature entirely - a badger. The tradition may have its roots in - yes, you guessed it - ancient Pagan celebrations of weather lore, where a badger or sacred bear would perform antics similar to those seen with today's Phil and Willie. Although the exact history of pre-American Groundhog Day is spotty, we know for sure that the event was first celebrated in the US in the 18th century by German-Americans in Pennsylvania. Today, celebrations occur throughout Canada and the United States, with the exception of Alaska where Marmot Day takes its place. Throughout North America however, it appears that groundhogs (and marmots for that matter) are equally bad at predicting meteorological events.

To learn more about Groundhog Day and its history check out this Wikipedia page. To learn more about "gophers" click here. Still curious about groundhogs and marmots? Click here!
And for those of you still intrigued by a rodent's weather-predicting capabilities, according to Punxsutawny Phil, we are set to have an early spring!
Happy Groundhog Day!

-Robert Niese
Education and Outreach Specialist
A California Ground Squirrel (Otospermophilus beecheyi)
A Least Chipmunk (Tamias minimus)
A Black-tailed Prairie Dog (Cynomys ludovicianus)
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