Stats on two threats to birds

Posted on March 11, 2011 by MadelineBodin

A study of a Wisconsin wind farm found that raptors mostly avoided the site, resulting in a big reduction of raptors in the area after the turbines went up. It also found that red-tailed hawks and turkey vultures took the most risks near the turbines, although red-tails were the only raptors found dead in the wind farm. Read the open-access article in The Journal of Applied Ecology here.

Also in the Journal of Applied Ecology, Dutch researchers found that birds breeding near noisy roadways had smaller clutch sizes than other birds. When the roads were noisy in April, the birds had fewer fledglings, regardless of clutch size. The species studied was Parus major. The paper, again, open access, is here.

How dense do coyotes get?

Posted on March 6, 2011 by MadelineBodin

The pack density of urban coyotes can be high, says a paper in the current issue of American Midland Naturalist. As part of a long-term study of coyotes in Massachusetts, the researchers observed that a pack of coyotes north of Boston was able to survive in a particularly small territory. The pack, they say, was of average size for the region: four coyotes in winter, six to seven in summer. But the pack occupied just two square kilometers. Read more here.

Find a free version of the paper here.

Box turtle data bonanza

Posted on March 2, 2011 by MadelineBodin

Courtesy of US Fish and Wildlife

The current issue of American Midland Naturalist has three papers on turtles, and two on eastern box turtles. The first box turtle (Terrapene carolina) paper examined the clutch size and clutch frequency of box turtles at the Wertheim National Wildlife Refuge on eastern Long Island, NY. The researchers X-rayed the turtles they hand-captured. About 40 percent of the females captured were found to have eggs.

The big surprise for the researchers was that the average clutch size was 4.1 eggs. A previous study conducted in Connecticut (just across Long Island Sound from the research site) was 6.7 eggs/clutch. Yet another study in Maryland reported an average clutch size of 4.6. The Long Island study also found that clutch size did not appear to be related to body size in any statistically significant way. The authors suggest that clutch size may have more to do with specific local conditions than general geographic location.

Another surprise was that 95 percent of the turtle eggs survived at nests protected against predators, suggesting that egg predators play a big role in the population dynamics of eastern box turtles. You can find the paper here.

In the second paper, Indiana researchers radio-tagged box turtles and followed them for two years. They found that 96.2 percent of the turtles they tracked survived annually. Winter survival was lower than survival through the months of the year when the turtles were active (95.6 versus 96.7). Get more information from the paper, here.

CWD in Maryland

Posted on February 15, 2011 by MadelineBodin

Chronic wasting disease (CWD) has been reported in Maryland. The Maryland Department of Natural Resources (DNR) reported last week that a white-tailed deer killed by a hunter last November in Green Ridge State Forest has tested positive for CWD. (Google Maps reveals that this state forest is in the Maryland panhandle, that little strip of Maryland between West Virginia and Pennsylvania.)

The Maryland DNR press release includes a link to the state’s 10-page long CWD response plan. (Actually, it’s two clicks away.)

The Baltimore Sun covered the story. Since the news broke, it also reported stories that the state’s deer harvest dropped below 100,000 for the first time in three years. And that a privately-funded research project is exploring the surgical sterilization of suburban deer.

Lack of photo: Sorry, but there are only so many pictures of CWD-stricken deer I can post in a week. This is Maryland’s state flag.

Shrew in a bottle

Posted on February 2, 2011 by MadelineBodin

North Carolina researchers found vertebrate remains in 4.5 percent of the open bottles they found on roadsides. The researchers recovered the remains of 553 small mammals, including five species of shrew and six species of rodent. They suggest that such an examination of roadside trash can be a way of surveying shrews without causing additional deaths in pit falls or snap traps. It’s also pretty good testament to the benefits of bottle refund laws.

According to the authors’ citations, the idea of using discarded bottles to survey the abundance of shrews goes back to at least 1966.

The study appeared in Southeastern Naturalist. Read more.

Measuring citizen scientist skill and effort

Posted on February 1, 2011 by MadelineBodin

Recreational bird watchers can provide a lot of data on species abundance, but how can you separate the effects of skill and effort from actual trends? Just look at the length of the species list, says this paper in the journal Ecological Applications. The length of the species list is a good indication of survey effort, when a few factors are considered. The paper tests and refines the List Length Analysis technique first developed by Australian scientist Don Franklin.

Photo: bird watchers at the Malheur National Wildlife Refuge, Oregon. Courtesy US Fish and Wildlife.

Counting parasites when hosts are hard to find

Posted on January 28, 2011 by MadelineBodin

In this paper from Conservation Biology, researchers counted what proportion of mud snails were bedecked with a trematode cyst that, as an adult, parasitizes terrapins. They felt this would be easier than directly counting diamondback terrapins on the Georgia coast. It has got to be a lot easier to ID a diamondback terrapin than a specific species of trematode cyst, but still, a very cool idea with the potential to be used in other hard-to-survey species.

Photo courtesy of the US Fish and Wildlife Service

Florida may delist black bears

Posted on January 25, 2011 by MadelineBodin

In June, Florida Fish and Wildlife Conservation Commission will decide whether to remove the black bear from the state’s threatened species list, a move that would open the door to hunting them. There are some interesting statistics buried deep in the Orlando Sentinel article, including that 8 percent of the bears in the WekivaOcala corridor are hit and killed by cars each year, on average.

Read the whole article in the Orlando Sentinel here.

A press release from the Florida Fish and Wildlife Conservation Commission from last November about the delisting process is here.

Photo credit: Waverley Traylor, courtesy US Fish and Wildlife Service

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