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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