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robins, NC/SC wildlife health alert, diseases and die-offs
- To: carolinabirds@duke.edu
- Subject: robins, NC/SC wildlife health alert, diseases and die-offs
- From: Joshua Stuart Rose <jsr6@duke.edu>
- Date: Sun, 10 Dec 2000 15:26:27 -0500 (EST)
- Sender: carolinabirds-owner@acpub.duke.edu
On Sun, 10 Dec 2000, Marsha Stephens wrote:
>
> Saturday and Sunday I have had 300+ robins gathering in the woods around
> my house. <snip> I have known this to occur here for the last 15
> years and I assume these are migratory. Is that most likely? Anyone
> else having such flocks of robins coming through?
Hi Carolinabirders,
"Migratory" might not be the best word to describe American Robins in the
non-breeding season. "Nomadic" is probably a better fit. They gather
together in massive numbers, and head off looking for food. With Robins,
as with Cedar Waxwings, "food" usually means fruits and berries. As the
fruit runs low up north, these species move south; they then spend the
winter romping from fruit source to fruit source across the south. For
example, a similar large flock of robins was residing near my house in
Durham weeks ago, eating wild cherries I think, and is now gone; another
was near my girlfriend's house more recently in a pair of crabapple
trees. And last winter (or was it the winter before) we had many posts
tracking the wandering of Cedar Waxwings around the area; they took until
February to show up in front of the Duke Biological Sciences building
where I work, attacking the Yaupon Holly trees there. So I would bet that
Marsha has some large, dependable fruiting trees near her house, and that
the robins remember this from year to year and come back for it.
Speaking of waxwings, interesting to note that the southward influx of
northern species seems restricted to raptors this year. Last year's
flights of crossbills and Bohemian Waxwings are not apparent. Must have
been some good berry and seed crops up in Canada this year... Speaking
of northern raptors, there are now two Northern Hawk-Owls in New
Hampshire where there was only one before. On the western vagrant front,
Varied Thrushes are being seen in both central Texas and Michigan. A
possibile thrush of a different stripe, from a different direction, an
alleged Fieldfare in Florida is awaiting confirmation.
Back here in North Carolina, the USGS has issued another warning about
the disease affecting the brains of American Coots and Bald Eagles, and
more recently Mallard Ducks. It has apparently now been found in a Canada
Goose. Woodlake, NC, and Strom Thurmond Lake, SC are the affected areas
so far. The message includes tips for waterfowl hunters and people who
encounter afflicted birds. This was posted to BIRDCHAT, along with
notices of a major botulism outbreak that killed about 8000 water birds,
including possibly 1000 Common Loons, on Lake Erie; a die-off due to
as-yet undetermined causes of nearly 500 Brant at Forsythe (Brigantine)
NWR in New Jersey; and a kill of over 200 birds of 16 species, including
Piping and Snowy Plovers, Black Skimmers, and Snowy Egrets, following a
mosquito-spraying operation near Marco Island. The latter operation used
Fenthion, a spray reportedly not authorized for mosquito control anywhere
in the US outside of Florida; hopefully Florida will wise up too... Scary
stuff, all around.
Good birding,
Josh
Joshua S. Rose
Duke University
Department of Biology (Zoology, R.I.P.)
jsr6@acpub.duke.edu
http://www.duke.edu/~jsr6/
------------------------------------------------------------------
>>Date: Wed, 6 Dec 2000 22:48:31 -0500 (EST)
>>AVIAN VACUOLAR MYELINOPATHY - USA (NORTH CAROLINA)
>>*********************************************
>>A ProMED-mail post
>><http://www.promedmail.org>
>>ProMED-mail, a program of the
>>International Society for Infectious Diseases
>><http://www.isid.org>
>>
>>[see also:Avian vacuolar myelinopathy - USA (Arkansas) 20000107.0016
>>Avian vacuolar myelinopathy - USA (Southeast) 20000606.0910]
>
>>*USGS Issues Alert for Deadly Disease in Birds*
>>-----------------------------------------------
>>A deadly bird disease, avian vacuolar myelinopathy (AVM), is affecting
>>mallard ducks and coots on Woodlake in North Carolina; coots on Lake
>>Juliette in central Georgia; and coots, bald eagles and -- for the first
>>time -- a Canada goose on Strom Thurmond Lake on the border of South
>>Carolina and Georgia.
>>
>>The disease has not previously been confirmed in Canada geese. Pathologists
>>at the USGS National Wildlife Health Center (NWHC) in Madison, Wisconsin
>>and the Southeastern Cooperative Wildlife Disease Study (SCWDS) at the
>>University of Georgia made the diagnoses.
>>
>>The USGS today issued a Wildlife Health Alert to natural
>>resource/conservation agencies in order to provide and promote information
>>exchange about significant wildlife health threats in their geographic
region.
>>
>>While there is no evidence AVM can affect humans, the risk to humans is
>>unknown. People should avoid handling wildlife having died from unknown
>>causes, or do so with caution using waterproof gloves or an inverted
>>plastic bag. Hunters should avoid shooting wildlife exhibiting unusual
>>behavior, use waterproof gloves when dressing out game, and thoroughly cook
>>meat before eating.
>>
>>Vacuolar myelinopathy is a nervous system lesion. In affected birds it
>>appears as open spaces in the white matter of the brain. Scientists have
>>determined the spaces are caused by separation of the myelin layers that
>>surround and protect the nerves. Affected birds may fly erratically or not
>>be able to fly at all. They may crash land, swim tipped to one side with
>>one or both legs or wings extended, or may be in the water on their back
>>with feet in the air.
>>
>>On land, birds may stagger and have difficulty walking; they may fall over
>>and be unable to right themselves (appear intoxicated). Birds are usually
>>alert and may bite when handled even if unable to escape capture.
>>
>>It remains unknown if the disease is "spreading" or if affected birds at
>>other locations are recognized because more people are aware of the
>>problem. All diagnostic, field and laboratory efforts indicate the cause is
>>most likely a chemical substance, either one naturally occurring or
>>manmade. It is unclear how the birds are exposed to the toxins.
>>
>>Many agencies are continuing field, laboratory and research efforts to
>>determine the cause of the disease. USGS-NWHC is conducting research on AVM
>>using mallards and coots in a sentinel study for the disease in North
>>Carolina. So far, the study has confirmed the disease is site-specific,
>>i.e. the lakes where birds are dying are the sites of exposure.
>>
>>Samples of water, vegetation, and sediments were immediately collected at
>>the locations where mallards were feeding. Feeding experiments are also
>>underway in an attempt to determine the route of exposure.
>>
>>Wildlife managers are encouraged to observe coots, waterfowl and eagles and
>>report any sick birds to the National Wildlife Health Center at
>>608-270-2400 or the Southeastern Cooperative Wildlife Disease Study at
>>706-542-1741. If any freshly dead birds are found, keep carcasses chilled
>>on ice or refrigerated, but not frozen, while you contact the above
>>agencies. For more information on AVM consult the USGS National Wildlife
>>Health Center website: <http://www.umesc.usgs.gov/nwhchome.html>