RR: Blowflies, etc.

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Great parasite lore, Alan. I think I might have met a few of the little
darlings.

Chris
--=20
Chris Maack
Bird Treatment & Learning Center
Anchorage, AK
-
From: "M. Alan Jenkins" 
Organization: Sutton Avian Research Center
Reply-To: raptors@theriver.com
Date: Thu, 25 Jul 2002 11:03:01 -0500
To: raptors@theriver.com
Subject: Re: RR: the myth of 'big' birds

--
Barry=20
Barry (read this BEFORE lunch ;-))
Those maggots are known as Protocalliphora, and are fairly common in the ea=
r
canals of nestling raptors and other species.  As far as I have been able t=
o
read, the only 'damage' they do is to enlarge the size and change the shape
of the bird's ear canal; I have not heard of them being lethal in otherwise
healthy nestlings.

Quotes from the Internet:

"Protocalliphora are calliphorids (blowflies) and like most other flies hav=
e
an egg, larva, and adult stage. Fly eggs are laid in nests or on nestlings
shortly after nestlings hatch. Larval development time varies depending on
the species of Protocalliphora, but takes 5 to 15 days, after which they
pupate. Pupal development takes about 7 to 10 days, after which adult flies
emerge."

"Blowflies
To understand how cavity nesters such as bluebirds interact with blowflies
and parasitic wasps, it=B9s helpful to understand these parasites=B9 life
cycles. Blowflies belong to the genus Protocalliphora. In North America,
Protocalliphora occur in Alaska, throughout Canada, in most of the
contiguous United States, and in parts of Mexico. Many different species of
Protocalliphora have been identified; a 1989 paper by Sabrosky and his
colleagues list a total of 26 species, including 15 newly identified
species. If you find evidence of blowflies in your nest boxes, it=B9s likely
that more than one species is present.

Blowflies spend the winter as adults outside the nest box, burrowed in leaf
litter, crevices in tree bark, or some other protected site. In the spring,
female blowflies deposit their eggs in nests containing very young
nestlings. Some species deposit their eggs directly on the nestlings. The
egg stage is short, probably 24 to 48 hours. This makes sense, as parasite
eggs laid in the nests of birds with short nestling periods must hatch
quickly to complete their development before the young birds leave the nest=
.

The larval period of the blowfly varies between 7 and 15 days, depending on
temperature, the host bird=B9s species, and the species of fly. Blowfly larva=
e
are obligatory blood-sucking parasites; they rely on blood meals to develop=
.
Timing is everything, for the parasite eggs must hatch and the larvae must
feed during a relatively short period. The larvae are small, grayish,
oval-shaped maggots about 1/4 inch long. During nest-box checks the larvae
can sometimes be seen attached to the fleshy parts of the chick=B9s head,
legs, or underwings.

After a number of blood meals, the larvae pupate. The length of the pupal
period varies widely=8Bfrom 9 to 36 days or more. Adult flies emerge, and if
the timing is right, they breed and lay eggs in the next available nest box=
.
Empty pupal cases are commonly found on the bottom of used nest boxes;
sometimes this is the only indication of blowfly parasitism. Pupal cases ar=
e
usually black or brown oval "pillows," approximately 1/4 inch long. Flies
that emerge at the end of the birds=B9 breeding season may find no viable
nests or chicks to lay their eggs on. These blowflies overwinter as adults
outside the nest box and lay their eggs in the spring, starting the cycle
all over again.

Blowflies are interesting creatures in their own right. Their offspring=B9s
survival depends entirely on their ability to lay their eggs in nests at th=
e
appropriate time. This strong selective pressure has produced an animal tha=
t
times its egg laying quite accurately."



Alan  Jenkins




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Great parasite lore, Alan. I think I might have met a few of the little dar=
lings.



Chris

-- 

Chris Maack

Bird Treatment & Learning Center

Anchorage, AK

-

From: "M. Alan Jenkins" <alanjenkins@ou.edu>

Organization: Sutton Avian Research Center

Reply-To: raptors@theriver.com

Date: Thu, 25 Jul 2002 11:03:01 -0500

To: raptors@theriver.com

Subject: Re: RR: the myth of 'big' birds



--

Barry 

Barry (read this BEFORE lunch ;-))

Those maggots are known as Protocalliphora, and are fairly common in the ea=
r canals of nestling raptors and other species.  As far as I have been =
able to read, the only 'damage' they do is to enlarge the size and change th=
e shape of the bird's ear canal; I have not heard of them being lethal in ot=
herwise healthy nestlings.



Quotes from the Internet:



"Protocalliphora are calliphorids (blowflies) and like most other flie=
s have an egg, larva, and adult stage. Fly eggs are laid in nests or on nest=
lings shortly after nestlings hatch. Larval development time varies dependin=
g on the species of Protocalliphora, but takes 5 to 15 days, after which the=
y pupate. Pupal development takes about 7 to 10 days, after which adult flie=
s emerge."



"Blowflies

To understand how cavity nesters such as bluebirds interact with blowflies =
and parasitic wasps, it=B9s helpful to understand these parasites=B9 life cycles=
. Blowflies belong to the genus Protocalliphora. In North America, Protocall=
iphora occur in Alaska, throughout Canada, in most of the contiguous United =
States, and in parts of Mexico. Many different species of Protocalliphora ha=
ve been identified; a 1989 paper by Sabrosky and his colleagues list a total=
 of 26 species, including 15 newly identified species. If you find evidence =
of blowflies in your nest boxes, it=B9s likely that more than one species is p=
resent.



Blowflies spend the winter as adults outside the nest box, burrowed in leaf=
 litter, crevices in tree bark, or some other protected site. In the spring,=
 female blowflies deposit their eggs in nests containing very young nestling=
s. Some species deposit their eggs directly on the nestlings. The egg stage =
is short, probably 24 to 48 hours. This makes sense, as parasite eggs laid i=
n the nests of birds with short nestling periods must hatch quickly to compl=
ete their development before the young birds leave the nest.



The larval period of the blowfly varies between 7 and 15 days, depending on=
 temperature, the host bird=B9s species, and the species of fly. Blowfly larva=
e are obligatory blood-sucking parasites; they rely on blood meals to develo=
p. Timing is everything, for the parasite eggs must hatch and the larvae mus=
t feed during a relatively short period. The larvae are small, grayish, oval=
-shaped maggots about 1/4 inch long. During nest-box checks the larvae can s=
ometimes be seen attached to the fleshy parts of the chick=B9s head, legs, or =
underwings. 



After a number of blood meals, the larvae pupate. The length of the pupal p=
eriod varies widely=8Bfrom 9 to 36 days or more. Adult flies emerge, and if th=
e timing is right, they breed and lay eggs in the next available nest box. E=
mpty pupal cases are commonly found on the bottom of used nest boxes; someti=
mes this is the only indication of blowfly parasitism. Pupal cases are usual=
ly black or brown oval "pillows," approximately 1/4 inch long. Fli=
es that emerge at the end of the birds=B9 breeding season may find no viable n=
ests or chicks to lay their eggs on. These blowflies overwinter as adults ou=
tside the nest box and lay their eggs in the spring, starting the cycle all =
over again.



Blowflies are interesting creatures in their own right. Their offspring=B9s s=
urvival depends entirely on their ability to lay their eggs in nests at the =
appropriate time. This strong selective pressure has produced an animal that=
 times its egg laying quite accurately."







Alan  Jenkins









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