State College Bird Club

October 26, 2016

State College Bird Club Meeting, October 26, 2016
Recording: Debra Grim
22 attendees


Checklist: 147 species reported

Treasurer report, Jean Miller: $660 received, $118 spent

Field trips: Bald Eagle State Park, TBA

Snow in Adirondacks may push ducks into our area.

November 16 meeting: The speaker will be Matt Toenies, a graduate student in Ecology at Penn State, who will give a program entitled "Winners and Losers in the


Changing Bird Community of Hemlock Forests."

October Speaker: Justin D Brown, DVM, PhD, Wildlife Veterinarian for the Pennsylvania Game Commission, The Natural History of Avian Influenza Virus in Wild Bird Reservoirs

Avian influenza has many combinations of subtypes H1-16 and N1-9, differing in severity. Highly pathogenic types like H5 and H7 cause 80-100% mortality in chicken flocks. Wild bird populations preserve the virus in a reservoir including more than 100 wild species, most commonly waterfowl, terns and gulls, shorebirds. The birds usually show no symptoms and carry low pathogenic types. The virus is constantly changing and always circulating, occasionally spilling over to other hosts such as chickens, pigs, or humans.

Big outbreaks in poultry that make the news are spread when domestic poultry are kept outdoors or via sharing of equipment and movements of people. Usually when the virus crosses from wild birds to poultry, it’s in a highly pathogenic form. We don’t know why chickens and other domestic poultry are so easily infected. Avian influenza costs millions of dollars in bird loss and cleanup. Even low pathogenic forms of the virus must be controlled in chickens.

S.E. Asia tends to maintain a reservoir because of the presence of wild birds in markets, mostly outdoor flocks, and less inspection and other safeguards. The virus can be carried from there to Europe and North America by migrating birds. In North America, the main source is wild birds. We need to learn to identify the pathogen in wild birds and discover how it infects domestic poultry.

Waterfowl, particularly dabbling ducks, have been known since the early 1970’s to be a reservoir. The virus presents as an asymptomatic intestinal tract infection and is easily shed via droppings into the water, where it can survive for weeks to months. The peak of infection is during pre-migration staging in summer, with 20-30% infection. This level drops as the waterfowl move south and disperse. Ducks were sampled in NW Minnesota in July through December 2007 and 2008; 27-35 subtypes of the virus were shown to be circulating. Birds sampled in Lakes Erie and Pymatuning in Pennsylvania showed the same pattern of peaking at fall migration.

Avian flu was discovered in shorebirds in the 1980’s. Studies show that ruddy turnstones demonstrate 90% concentrations of the virus when they gather in May at Delaware Bay, always a different type. It is thought they acquire the virus at the Bay, then quickly become immune. Red knots, however, arrive already carrying antibodies—it is not known where they became exposed. Sanderlings have no antibodies—they are either resistant or never exposed.

H13 and H16 is endemic in gulls, particular in pre-fledge chicks. Other Laridae are not well studied. Geese and raptors are susceptible. Terrestrial birds are not a good reservoir.

Surveillance needs to continue: watching for sick birds, sampling waterfowl, and testing dead birds of many kinds.

Minutes by Debra Grim