Migration
To better understand the problems of migratory birds you should first know
a little about migration itself and the complexities of migrating long
distances. To explain it all would take volumes, but this will give you an
understanding of the problems birds face during these treks around the
world. More than half of the 9000 species of birds migrate regularly. It
can be as short as a biannual trek up or down a mountainside or along a
stretch of coastline, or it can be as long as an intercontinental journey.
No matter what the distance, most species return to their nesting grounds
with the change of each season. In the Arctic regions of Greenland,
Alaska, and Canada where most shorebirds nest, the entire population
consists of birds that only are there during the summer months. In the
colder climates of the eastern United States 80% of the birds are
migratory, spending the winter months in the warmer southern climates.
When food sources dwindle, their biological clock tells them they must
leave to warmer climates in order to survive. In areas where food supplies
vary from year to year migration may also vary. In the far north, the food
supply always disappears at the same time, so birds have no choice but to
leave on schedule each year. An example of varying schedules are the
Chimney Swifts that have come to spend the summers in my big stone chimney
every year since we built the house in 1984. They arrive here from Peru,
where they spend the winter. They will arrive at approximately the same
time each spring normally around April. They have their babies in June and
leave late August or early September each year. Their diet consists
entirely of insects that they eat on the wing, so in the summers that we
have very little rain and the insect population is down they will leave as
early as August 1st. One summer we had a lot of rain and their nesting was
not successful, many of the young died, they left early then also. This
past summer everything seemed to go well and they were in the chimney
until the middle of September.Bird migration has
evolved over thousands of years and continues to evolve today because of
the changing environmental conditions. In the absence of predators and a
plentiful food supply some birds will abandon migration when the advantage
no longer exists.
Altitudes may vary greatly among species. Night migrating song birds fly
at an altitude of about 5000 feet, but the majority will go no higher than
2500 feet. Waterfowl and shorebirds travel higher at altitudes of 10,000
or as high as 20,000 feet when making long journeys over water. The most
significant influence on altitude is weather. If it is cloudy or overcast
they may ascend through it to reach clear skies. If favorable tailwinds
are found at certain altitudes, they will ascend or descend to take
advantage of them.
Seabirds are especially adapted for covering great
distances. They can travel the length of the oceans and back again, a
25,000 round trip every year of their lives. To do this the bird needs
lots of body fat. As their biological clock tells them it’s getting near
time to migrate, their metabolism changes and they begin to store fat
under the skin. It can actually equal half their body weight. Most of
those reserves will be used up on the first leg of their journey, so it’s
very important that they be able to stop along the way and replenish their
fat reserves. Therein lays one of the major problems. The migration routes
have been established since the beginning of time. The wetlands and
coastal areas that these birds have used are now being filled in and built
upon, water sources polluted. Food sources have dwindled and so have the
birds. One only has to look at photographs from past generations of the
large, beautiful flocks of birds that used to be taken for granted and
compare them with the flocks found today. They used to number in the
millions.
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MIGRATORY
BIRDS
The majority of migratory birds that I get are juvenile, probably hatched
the previous spring and this is their first migration. Some simply do not
fare well because they have not been able to store enough fat to keep
their strength up for the long ordeal, and are unable to find sufficient
food sources along the way.
Some people will argue that it’s simply nature’s way and we shouldn’t
interfere. They neglect to realize that we’ve already interfered by
destroying their habitat, poisoning their food supply, and injuring them
with our carelessness. There is no answer to the problem except to do what
we can to get as many of these birds as we can back into the wild to
migrate and propagate another year.
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Sea
Gulls and Terns
Anyone living in coastal areas of this country will more than likely come
in contact with a number of sick and injured water birds and shorebirds.
In the southern coastal areas the winter months bring the migratory birds
in large numbers. Federal laws protect all migratory birds, so when found
in distress, a wildlife rehabilitator licensed with the Dept. of the
Interior should be called to pick the bird up and care for it. They are
also responsible for keeping records of all migratory birds coming into
their shelter and the disposition of these birds. This gives the governing
agencies a reading on the health and well being of migratory birds across
the country. If, however,
you cannot find anyone in your area and are left to care for it yourself,
a few common sense steps can save the bird’s life so that it can be
returned to the wild. The majority of sea gulls that I receive has been
weakened, wings drooping, and cannot stand on their legs. This is called
sick gull syndrome and has a variety of causes, the two most common is
avian botulism and salmonella, both caused from eating contaminated food.
They can also have basically the same symptoms from toxins such as mercury
found in fish. Runoff into water sources from lawn fertilizer or
pesticides kill large numbers of water birds each year. When a bird comes
in showing these symptoms should be placed in a warm environment, around
85 degrees to bring the body temperature up. If the bird is holding its
head up, but just can’t stand, then place a shallow bowl of 50/50 Gatorade
and water in front of the bird so that it can drink without having to
struggle to reach it. Change it often to keep it fresh. Usually they will
not eat when food is placed in front of it, but they will always drink
because they are dehydrated. Amazingly, in many cases, in a few days they
will begin to get onto their feet and walk around.
At this point you can begin offering food. I find a can of cat food mixed
with a piece of bread and placed on a saucer in the cage goes down easy
with a weakened bird and is nutritionally balanced to help it regain
strength.
Once it has recovered, you can give it
cut up bait fish, or continue the cat food until it is released. When the
bird is fully recovered and eating well it is time to release it at a spot
where there are other birds of the same species.
That is, sea gulls where other flocks of gulls are
observed, pelicans where other pelicans are, and so on.
Rehabilitation of Terns is basically the same as above.
They are not as aggressive as the gulls so do not try to cage them with
gulls. Sometimes you cannot put two gulls together, so if you attempt it,
carefully observe their behavior to insure that one does not attack the
other. This should be said about all wild species because they are under
tremendous stress from captivity in the first place and their instincts
may be to attack anything that is threatening.
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Pelicans
Winter months along the coastlines are sometimes difficult on pelicans,
especially the immature ones. Since they have to dive for their food, when
the water gets colder and the fish go deeper, it is difficult for them to
find enough fish to keep themselves well fed. Especially the younger ones
which have not yet developed the feeding skills the older ones have. They
will become weak and lethargic. If there are no signs of trauma and no
labored breathing, then one can assume that they just need to be fed.
Pelicans are extremely finicky about what they eat. Where a gull will eat
almost anything you put in front of it, a pelican will only eat whole
fish. Usually a bait shop or marina will donate fish if you explain what
you’re trying to do. If not, you may have to resort to buying frozen bait
fish. Place three or four thawed fish in a shallow pan and place in the
pen with the pelican. It will almost always eat on its own once it settles
down. If the bird is too weak to feed itself, or on the rare occasion
where it absolutely refuses to eat, then you will have to tube feed it.
Not as hard as it sounds. A turkey baster works very well. Place a can of
cat food in a blender and as a small amount of water at a time until it
becomes pureed enough to flow through the baster.Hold the mouth open, put the tube far down into the throat, noting the
birds breathing hole at the base of its mouth. Slowly squeeze the bulb of
the baster until the cat food is out of the tube. Wait to make sure it
goes down, then repeat the process. Once a day is enough until the
strength is regained and it is eating on its own. If you try to force feed
whole fish, they will deliberately regurgitate it back up
Another common problem with pelicans is heavy metal poisoning, usually
found in groups swimming in waters surrounded by development. When people
spray pesticides on their lawns and use fertilizers, the run off produced
by storms or normal levels of irrigation flows directly into the water and
can have devastating effects on wildlife. These birds will act as though
they’re drunk and disoriented, many will have seizures. A shot of atropine
by a vet may counteract the toxins, but unfortunately by the time they are
found the effects are permanent and almost always fatal.
All water birds can fall victim to toxic poisoning and should be taken to
a veterinarian as soon as possible, then rehabilitated in a quiet, stress
free environment. If you’re forced to keep the bird out of water for
several days while it is recuperating, their feet should be coated with
baby oil or KY Jelly to prevent the skin from cracking.
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Cormorants, Anhingas, Herons, Egrets, Moorhens
All of these birds not only fall victims to poisoning, but tend to come in
contact with fishermen’s hooks and monofilament line, as do pelicans.
They have the very dangerous habit of going after the fish at the end of
the line thrown into the water by a fisherman. Unfortunately, most of the
time the fisherman cuts the line and the bird flies off with line dangling
behind it.
As time goes by the line will tighten around legs, wings, or get caught on
rocks or plants. The hook should be pushed through, the barb cut off and
the hook removed as soon as possible and all of the line cut away from
around the bird. If the bird has swallowed the fish and hook, enough line
should be left dangling from its mouth so that a vet can get hold of it. A
skilled veterinarian can sometimes remove the hook from the stomach and
the bird can be released. If these birds show signs of weakness or the
other illnesses described above, they should be kept in a quiet cage, a
shallow bowl of water and constant supply of food. Cut up bait fish for
the Anhingas and cormorants, and meal worms and seeds for egrets and
moorhens. All sick and injured birds should be kept in a warm, comfortable
environment.
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Capture of Shore Birds
One very important note to remember before attempting to catch one of
these birds is the sharp beak they possess. These birds use their sharp
beaks to stab fish. Cormorants and Anhingas in particular have such beaks.
They will instinctively stab at your face and can put your eye out, or at
least give you a very painful stab wound. Always wear gloves and try to
catch them by throwing a large towel or sheet over the bird, keeping the
head covered. That way you can scoop the bird up and safely transport it
to a carrier. Always keep your face at a safe distance.
Pelicans, despite their large beaks are relatively easy to handle. They
try to intimidate by whacking at you with their beak, but with a pair of
gloves, you can simply grab the beak and hang on. They are totally
helpless at that point and you can put their wings to their side and scoop
them up. Hang on to that beak! They do have a serrated edge to the inside
of their beak and can give you a little cut if your hand comes in contact,
but gloves will eliminate that. A sheet can also be thrown over the
pelican and scooped up as with the other birds.
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Stress in Shore Birds
Some birds are very difficult to keep in captivity for any length of time
because they stress to the point of death at being caged and handled. The
Blue Heron, the Cormorant, and Anhinga, can actually die from being
handled. It is extremely important to keep these birds in a quiet
environment, as large a cage as possible and handle them as little as
possible. Hopefully they will eat fish from a shallow pan, on their own,
because to try to force feed these birds can easily kill them from stress.
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Common Loons and Northern Gannets
These birds have a paragraph all their own because of their unique
anatomy.The Common Loon has legs very far back on their body, their feet are
webbed, but they are much more like flippers that duck feet. They are
designed for water, not land. Loons spend 90% of their life in the water.
They will rest along the shoreline, but if stranded on dry land away from
water they are totally helpless. They cannot walk on land and cannot take
off in flight from dry land, so if they end up on a beach as they
sometimes do during migration, they are stranded until the tide comes in
again. They are really more at home in the calmer waters of a river, so
even if there are no signs of trauma or illness, it is usually better to
take them to a river or lake and release them as quickly as possible. They
migrate from the rivers and inland lakes of Maine and Canada and when
thrust into human contact become extremely stressed and will not survive a
lot of handling.
If they are weak, ill, or wounded and cannot be released, then do not keep
them in a small confined area or you will soon find them dead. An old
child’s play pen will give them adequate room. Since they are built for a
life in the water, when on hard surfaces, they should be kept on a very
soft cushion to prevent extreme discomfort to the breast bone. An egg
crate mattress pad or a downy comforter will do. A shallow pan of water
and bait fish in front of them will sometimes induce them to eat on their
own if they are relatively stress free. They do not regurgitate their food
like some of the others do, but when trying to poke a fish down their
throat, be sure to wear gloves.
They have very strong beaks and will also jab you if they get a chance.
The Northern Gannet also has legs far back on their body, but they can
walk on land. They are more designed to walk on rocky cliffs than flat
land, so they are almost as helpless as the loon when stranded. They seem
to be very prone to large die-offs of recent years. Researchers are trying
to find out why, but not much is really known. Both Loons and Gannets
should be kept in captivity as little as possible. Out of water, they just
don’t seem to last very long. When in doubt, it’s sometimes best to force
feed a fish or two, and release into a river or lake, giving it at least a
fighting chance with Mother Nature. ALWAYS wear gloves when handling or
feeding these birds. Their beaks are like vices and can take a finger off.
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