Common Habits Of
The Purple Martin
Purple Martins are a very interesting bird. Their
habits around the colony have been studied for years and if not
understood, can be very disconcerting to the 'novice landlord' or
'landlord to be' trying to attract them. Many myths have been passed
down through the ages about these birds from people who themselves
didn't fully understand them, thus making it even harder for the
novice to understand them. Let's look at a few of the daily routines
of martins and maybe some of this will make understanding their
daily habits and activities a little easier. Just remember,
individual pairs may vary, and their individual actions may also
vary as well. If you see something happening in your colony that you
don't understand, pay attention to what's going on, make notes and
then, if you can't figure it out, discuss it with an expert. There
are also many very experienced landlords around. Get to know them.
They may even be able to help.
Also, the PMCA is a great
place to get answers from one of the worlds most authoritative
experts on purple martins, James R. Hill, III. His in-depth studies
of purple martins have disclaimed many an old time myth of this
beautiful bird species. The email to the PMCA is
'pmca@edinboro.edu'
On this page I will attempt to describe
some of the activities that happen under normal circumstances on a
daily basis in and around a purple martin colony. And again,
remember, even though this bird species is very friendly towards
humans, we're still dealing with nature and wild creatures, so
anything is possible at anytime. They still have all the wild traits
that all wild birds have and will at times follow these natural
instincts and leave us wondering what in the world they're doing.
Sometimes the only things we can do are 'Look, Listen, and try and
Learn'.
Understanding The Different
Birds
It's early spring, the sun is getting higher in
the sky and the weather is warming. For the prospective martin
landlord, anticipation is running high. We have our housing up and
have followed all the rules we were suppose to. Now all we need is
for some martins to arrive at our house.
Before all this happens and to understand the migration,
you have to first understand the different stages of the
birds.
First, purple martins are what is called sexually
dimorphic. This means the males and females have different
plumages. However, there is another kink to be thrown
in. Purple martins also display what is called delayed
plumage maturation. This means that the mature birds are
the ones that show the true colors and not the young birds.
Now, we have to understand that there are three different
stages of birds.
The first are HY (Hatching
Year) birds. These are birds that have just hatched and are
in their first year of life. Obviously, these birds are fresh out of
the nest, are just learning to fly and have not made any migration
trips. Sexual identification of these birds is practically
impossible.
Next, there are SY (Second
Year) birds. These are birds that were born last summer, have
made one trip south, are returning and are in their second calendar
year of life. These birds have not yet nested and still contain the
sub adult plumage. Although difficult for the beginner, sexual
identification is possible.
Finally, there are the ASY
(After Second Year) birds. These are birds that
have made at least two trips south, have molted away their immature
feathers, have obtained their adult plumage and are in at least
their third calendar year of life. These are birds that have had a
chance to nest at least once, possibly more. Sexual
identification of these birds is very easy because of the mature
males' total black cloak of feathers.
To help distinguish the
ages, look at the pictures here.
Chronological Colony Life
Usually the first
birds to return are the older ASY birds. These birds are often
established in a site somewhere and will usually return to that site
to do their nesting each year. This is known as 'site
fidelity'. Since they have successfully raised young at that
site before, they feel safe enough to return to that same site to do
it again. Although not always, the males are usually the ones to
arrive first. These early arrivals are usually known as
'scouts'. Because of the nature of martins to show up at a
site for a period of time, then disappear for days, it was once
thought that these birds arrived first to check the site out and
then returned for the rest of the flock, but this 'longtime myth'
has been dis-proven. The other birds simply arrive when they are
ready.
Once these early birds arrive, they set about getting
to know the area again and simply lounge around until more birds
arrive. This is why you may see them for a short while and then they
disappear for long periods of time, even days. They are in no hurry
to do anything. Martins are superb fliers, spending many hours on
the wing finding food or just plain enjoying life.
Once the
females start arriving, the males begin selecting as many of the
adjacent compartments in the site as they can successfully
defend. (Known as 'male porch domination). This is done
with the intent of possibly attracting more than one female to mate
with. They then seek out the females, attempting to court them and
persuade them to set up house keeping with them. Again, the females
have just arrived and are in no hurry to settle down. This is when
the males are most vocal, chasing after and courting the females,
insisting that they investigate the cavities that they have
claimed. An interesting point here, females don't pick the
males. Instead, they investigate the cavities he has chosen
and if they like the cavity, then they will stay with that
male. Often, if they survive the migration, the same pairs
will mate each year providing he has the same good cavity. Once
she's made her decision, the pair will strengthen their bonds, the
male following her everywhere she goes, protecting her from other
males while at the same time, trying to attract more females to his
other cavities if he possesses them.
About 4 to 6 weeks after
the ASY birds have arrived, the SY birds will begin filtering in.
These are the birds that were born the previous year and have not
yet nested or even selected a site. Since they are not already
established in a 'site', they begin looking for a place to start a
home. These are the birds that are usually attracted to new sites to
start new colonies. Upon first arriving in an area, they also are in
no hurry to start nest building or egg laying. They instead, flirt
around the different homes they find, investigating all available
ones until they find something that they consider interesting.
This is why it's imperative that new potential landlords make their
sites as appealing as possible.
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One unusual thing the
established males do is attempt to attract other males to the site.
This is done with hopes of breeding with any females that they in
turn may attract. (This is known as forced pair copulation).
This is especially done with the SY birds, since they have not
nested yet and may not know how to defend their females. All the
time they are doing this, they are trying to defend all the holes in
their immediate territory for more possible females. If the young
males do decide to stay, they in turn will try to attract other
females. This is one of the most active times around the site and a
lot of noisy chattering, fluttering and squabbling will take
place. Plus, it's one of the ways a site will
grow.
After a few weeks of lounging around, the older birds
will settle down and nest building will start. Nesting may be spread
out as much as a month because of the different ages of the birds.
Both birds will make nesting material gathering flights, but it is
usually the female that ends up doing most of the work. The male
will usually make flights with her to hurry her on and to also
protect her from other males while she is on the ground. This is
when she is most vulnerable against the forced pair copulation from
other males. This nest building usually lasts from about 3 days to 2
weeks for each pair. The material they gather may vary from grasses,
pine needles, (pine straw), sticks, small stones, mud and fresh
green leaves. Even things such as gum wrappers and cigarette butts
may be found. The mud is usually used to make a dam in the front of
the nest leading up to the entrance hole. Most of the time, these
mud dams are built in the smaller nesting compartments and is
thought to be protection from the elements. The reason for the green
leaves is not actually known, but they are believed to keep the eggs
moist and usually cover the eggs with them when they leave to forage
for food. The birds will replenish these leaves from time to
time.
In the back of this nest, the female makes a small
depression or bowl, and when nest building is complete, it's here
she will place, depending on her age, anywhere from 2 to 7 soft
white eggs. The SY pair will usually lay smaller clutches of about 3
or 4 eggs while the ASY pair will often lay 4 or 6 and sometimes
even 7.
Not surprisingly there is a second factor that will
sometimes dictate how many eggs are laid. If the nesting cavity is
larger in size, such as a 7" x 7" x 10" cavity or a 10" diameter
gourd versus a 6" x 6" x 6" nesting cavity, the average number of
eggs laid will surprisingly increase in number. Apparently, with the
extra room, they will lay more eggs. It's very common for mature
birds to lay 7 eggs if there is room for them to do so, however
there also has to be abundant food available to feed the
young.
Once egg laying begins, eggs are laid at the rate of
one per day, usually in the morning around daylight or shortly
after. (This is how a landlord, doing 5 day nest checks and keeping
good records, can tell when egg laying started and thus approximate
when hatching will begin). Actual incubation begins with the laying
of the next to the last egg. The incubation stage of the nesting
period will last for about 16 to 18 days with the female doing most
of the incubation. During this period, the males will simply sit
around or fly off to gallivant on the breezes of the day.
At
the end of this incubation period, the eggs will hatch within a day
or two of each other. Young martins are born featherless, a term
known as Altricial. (Birds born with feathers are known as
Precocial). Once all young are hatched, the brooding stage
begins and will last for about 28 days after which time the young
will fledge. This is probably the busiest time for the adult
martins, having to gather enough food to keep the young fed. Trip
after trip has to be made to supply the ever hungry, growing
fledglings with enough food so they will grow into birds that are
ready to fly within 28 days. About a week to 10 days before the
young fledge, they can be seen poking their heads out of the
compartment entrance hole, taking stock of the neighborhood while
waiting for the parent birds to return with more food. This is an
anxious time in the colony. Predator attacks become more prevalent
when there are a lot of young present. It's a must to have predator
guards in place during incubation and brooding times. Many predators
would love to get at the eggs or young martins and make a meal of
them.
Since all birds don't start nesting at the same time,
this activity period will be spread out over about 4 weeks. Some
compartments will be busy while others will not. But, once eggs are
hatched and young are present, the activity level for that nest
increases greatly. Regular nest checks by the "Landlord" will keep
him/her fully informed as to the condition of the site and the young
in it.
At about three days before the young fledge, they are
about the same size or even larger than the adults. At this time,
they're probably too heavy to make that first successful flight. The
parent birds seem to know this and will stop feeding them. This
causes the young to lose some weight, thus enabling those first
crucial flights to be successful. The parent birds can be seen
trying to encourage the young to come out of the compartments and
fly. With enough observation, a landlord might even catch sight of a
parent pulling a young one out of the entrance hole, trying to get
them to take that first leap.
Upon exiting the nest, the
young will take off with much excitement. The parents will often
chase and harass the young, screaming at them, seemingly scaring
them into flight. This first flight is a crucial one. They have to
learn to fly, and they have to learn to fly well, quickly. Their
life depends on it. There are many predators that are waiting on the
young and they have to be able to fly very well in order to evade
these predators.
Once fledged, the young will practice
flying, landing and taking off again, returning to the site
occasionally for a rest and they may even spend a night or two in
the compartment, but they will not stay long. For about a week, the
young will practice flying while still begging for food from the
parent birds. Often, they can be seen on nearby power lines or open
trees, begging for food from the parents and waiting for the parents
to feed them. But, as nature will have it, all good things must come
to an end and the young have to start feeding themselves. They will
now have to put their practice flights to use. They will start
hanging out with the adult birds, learning how to feed themselves
and beginning to enjoy the start of their lives, investigating
everything that is around them. They will visit any and all houses
that they find in the area, making mental notes of the area where
they were born. Although most of these young will not return to the
site of their birth, they will usually stay within a 25 to 50 mile
radius. This helps to keep inbreeding at a minimum. This is why your
housing should be left up until the birds have gone for the summer.
These practice flights of other young will include investigating
your house and just maybe they'll return to your house next
year.
After a couple of weeks of this, the entire flock will
now start gathering in 'communal staging areas'. This is an
area where birds from the general area will gather, readying
themselves for the long and arduous flight south to their wintering
quarters in South America. The groups will be small at first, but as
more birds join in, they will grow in size. Although not always,
these gatherings are usually around areas where there is fresh water
present. They need to drink, and water usually harbors thousands of
insects, something they need to gain the energy that is required to
make the long trip south. Except for a few late nesting pairs, it's
at this time that the small individual sites will become void of
birds. This is a sad time for the landlord. Their birds are leaving
for another long winter. But, we as landlords shouldn't be sad. This
is what our hard fought efforts were all about. To attract birds,
have them successfully raise young, and then watch them fly away
into the sunset. A cycle that is repeated year after year at site
after site.
It's now late summer, the sun is retreating lower
in the sky, the weather is getting cooler, anticipation of fall and
winter is running high. It is now time to take the housing down,
clean it out and fix any and all problems with it. Might even need
to paint a gourd or two. We've done everything we were told to do
and we successfully fledged some baby martins. Now, all we have to
do is wait for spring to do it all over again, and that's just
around the corner.
Some questions and some
possible answers...most are common occurrences around a purple
martin colony.
I've been told that I shouldn't
bother the birds during nesting or they will leave...
Not
so. That was your mother's way of telling you to leave the
birds alone when you were a child, otherwise, not knowing any
better, we would have disrupted the nest. However, it's a
proven fact that when regular nest checks are done on a purple
martin site, more and healthier young are produced than one that has
been left to its own accord. The landlord that is involved has a
much better handle on the activities or problems that may arise in
the colony. With these regular nest checks, good records are able to
be kept, and the landlord is then able to give immediate attention
to problems and correct them before anything detrimental happens to
the site. Landlords that are out, around and under their housing
every day will get to be known by their birds and the birds will
quickly begin to trust them. Soon, their presence is practically
ignored as the martins go about their daily activities. Contrary to
common belief, the martins will not mind at all if you temporarily
invade their nests. In fact, if done right, after some time, some of
them won't even get off the nest but will stay there and ride the
housing down and then back up. This is the ultimate trust from your
birds.
How often should I do my nest
checks?
Once a week is probably fine to start with during
the nest building stage, but as egg laying begins, every 4 or 5 days
will give the landlord a much better handle on what is going on in
the colony and will enable him/her to quickly correct any problems
that may arise. Don't need to over do it but it's good to know how
nest building is going, if and when the first eggs are laid, when
the first babies hatch, are nest parasites a problem, etc. Because
of the time schedules associated with nesting, approximations can be
made as to when the young should fledge. Also, good record keeping
is a must. There are sheets available from the PMCA that help
tremendously in keeping track of all the info.
My birds
are sitting on my house. Suddenly, one will they take off, screaming
at and chasing other martins. What is going on
here?
These are usually males that are trying to attract
other birds to your site. This is good for you. They're actually
trying to increase the size of your colony and that's what the whole
thing is all about. The males are usually the vocal ones of the
species and are the chatterboxes of the groups. It's their loud
vocalizations that draw other birds to the site. Once they spot
another potential 'site mate', they take off after it, calling
loudly to get its attention and to try and attract it to come down
to the site and join them. Sometimes it might be other males, and
sometimes, it might be females with the hopes of
nesting.
Note: This activity, although ongoing
throughout the day, is usually most prevalent during the nest
building stages.
There is also another thing that you might
notice. In the very early morning hours of pre-dawn, male
martins will sit out on their housing and sing their song to try and
attract other martins to the site. This is known as 'dawn
singing'. Their calls seem to carry further on the early
morning air. Cassette tapes and CD's have been made of these
vocalizations for landlords to play with the intentions of
attracting martins to their sites.
Help, I'm being buzzed by my birds...they fly off the
housing to buzz very close to my head while chirping very
loudly.
If you're being buzzed by your birds, (a term
known as strafing), it's because you're not spending enough
time with them. This often happens when birds start nesting and the
landlord doesn't pay them any attention. If you as a landlord don't
spend any time with them, they are not having any human contact and
therefore, are viewing you as a stranger or intruder and thus are
buzzing you to protect their area. This is a very common activity
around martin sites and will happen every year, especially with new
birds that have arrived at your site or when there are young in the
nests. But, the birds are harmless to humans and no harm will come
to you because of it.
The solution: Spend more time in and
around your colony, doing walk unders, and talking to your birds.
(No I'm not joking. They actually get to know your voice). They will
soon become used to you being around and the buzzing will stop. (And
no, your neighbors or family won't have you committed for talking to
your birds).
My birds are fighting. How do I stop
it?
You don't. Fighting in a purple martin colony is a
common occurrence and you will witness it all the time. They will
very often fight all the way down to the ground. Remember, they are
fighting for a reason. They have laid claim to an area and they
consider it their territory, therefore, if invaded by another bird,
will fight for it. Maybe they are both after the same gourd or even
the same female. They will also do the same with Sparrows and
Starlings, two of the martins worst competitors.
My birds
are here in the early morning and late evenings, but nowhere to be
seen during the day. Where do they go?
This is very
common around a purple martin colony. Martins eat insects. Also,
martins are superb fliers and spend many hours on the wing. They can
easily spend 4 or 5 hours a day on the wing in search of insects for
food or just plain enjoying the thermals. Since martins eat only
insects, they will range far and wide to get them and may have to
spend long periods looking for them. Once fed, they will return to
the site and sit and preen themselves. They are just enjoying life,
so don't fret, it's what they do.
The SY birds are
bothering the young ones that have just fledged. What can be
done?
Nothing. This is another common occurrence in a
martin colony. Often, in a colony, there are bachelor males that are
not able to attract females and are known as 'floaters'. Although
not always, these are usually SY males. These birds will often
harass the young to try and drive them from the area. It all has to
do with competition. For nests. For food. With the young driven off,
there is less competition, thus living is easier.
I did a
nest check and found 4 dead babies in one of the nests. What
happened?
There are a number of things that could be the
problem here. Inspect the babies. Do they seem to be in good
condition? If so, then something could have happened to the parents
and the babies ended up starving to death. The death of one parent
will often make the other one abandon the nest, and thus the young
parish.
Do the young have peck marks all over their heads and
bodies? If so, then you have problems with pest birds such as
Starlings or Sparrows invading your nest and killing your young.
These birds are very aggressive nesting competitors and will often
destroy the eggs or kill the young or parents. If this is the
problem, then an aggressive trapping program should be set in place
to rid your site of them.
You may have seen 'floater' martins
around the site. It has been thought in the past that these birds do
harm to the unfledged young, but there is no documented cases where
these birds will harm young. Yes, they will chase and harass flying
fledglings, but that is because of the competition for nesting
sites. They are trying to drive the young from the area so there
will be less competition for nests next year. They have never been
known to harm young that are still in the nest.
If the young
seem to be unharmed, check the nesting material. Are there things
such as chicken mites or blowfly larva in it? If so, then there is a
good chance that they may have killed the young. These parasites
feed on the young birds, and if the infestation is very bad, then
they can drain a young bird of enough blood to cause it to die.
Sometimes, if the infestation is bad enough, the young will jump
from the nest rather than die from the incessant biting from these
pests. This is a common problem in the south where the insects like
the warm weather. Complete nest replacement is the number one
action, with a teaspoon of DE mixed in the new material. Another
reason for easy access to the compartments.
I found a
single dead baby martin on the ground near the house. What
happened?
Again, there are a couple of different things
that could have happened. One, if the baby bird looks in good
physical condition, then the parent birds must have noticed
something wrong with it and removed it from the nest. This is a
common occurrence. Nature has a way of insuring survival of the
fittest, and when parent birds of all kinds feel there is something
wrong with a young one, they will remove the potential problem
leaving the remaining ones to grow healthier and stronger.
If the
young bird has peck marks, then it is the work of the Starlings or
Sparrows again. Set up an aggressive trapping program to remove
them. And don't just relocate them, or they will return the next
day. Destroy them so they are gone for good.
My young have
fledged, but are not interested in staying in my housing. Why
Not?
The nesting period is the most dangerous time for
birds. The building of nests, the laying of eggs, constant flights
to the nests to feed the young. All this commotion attracts the
attention of predators. The longer the young are in the nests, the
more susceptible they are to attack from these predators. For
instance, snakes and raccoons can smell the young in the nest, and
make every effort to get to them. Also, the young in the nest make a
lot of noise that can attract other prey birds such as owls,
therefore it's in their best interest to vacate the site as soon as
they are able.. Once out, the young are more susceptible to flying
predators such as acipitor hawks. This is why the have to learn to
fly very well, very quickly. Once out of the nest, they might return
for one or two nights, but soon join the adults roosting in trees or
on power lines, practicing flying and readying themselves for the
long flight south. They will still fly overhead, but will not stay
in the housing anymore.
I had 4 nesting pairs that raised
12 young. Does that mean that I will have 20 birds return next
year?
No! There are a number of factors to be considered
here. The death rate on migrating martins can be high at times.
Storms, predators, age, exhaustion from the migration flight, lack
of food. All factors that may ultimately end in death.
Also,
nature has devised other plans for the young. Although born in one
site, they do not all return and seek out this site the following
year. They instead return to the general area, say a 25 or 50 mile
radius, and then start searching for a place in which to nest. This
is one of natures ways of preventing inbreeding. Although sad for
us, this is good for the species in general. It's a natural way for
the species as a whole to build immunities that will ward off
infectious diseases that could annihilate entire flocks if allowed
to propagate. It has been shown through testing and banding that
only about 1 in 5 will return to the same site that they were
fledged from. Sad, maybe, but look at it this way. While your
fledglings will leave your site to go to other sites, other
fledglings from other sites will come to yours.
My birds
are all gone. Is there anything I should do to my
site?
Although not immediate, this is a good time to take
the housing down and clean it out. Now, some say that it is not
necessary to clean out old nests, and there have been tests done
that show that the martins will readily return to old nests, but I
like to clean mine out and here are my reasons. Old nesting material
will harbor parasite larvae that feed on young martins. I like to
remove them by destroying the old nests. Also, since I use gourds, I
like to remove the old nesting because it will hold moisture, and
that will hasten the decaying of gourds. Even though I've treated
them to last longer, I just like the idea of putting up a nice clean
gourd each spring. Once I have things ready to go up, I can place
new nesting material in the cavities. (Pine straw in my case). The
birds accept this material just as well as the old nests from last
year and I feel more comfortable.
If your housing does not
raise and lower VERTICALLY then this should also be fixed. Housing
that tips to get at it should be replaced with or reworked to
housing that will raise and lower with the house in the upright
position. This will then allow you to do nest checks on a regular
basis without dumping eggs or young out of the house.
Another
thing that can be done is to fix any potential problems with the
site such as loose housing or frayed ropes or cables. If your
housing is of the kind that does not allow access to the
compartments for nest checks, then now is a good time to update the
housing so this can be accomplished. If you have gourds, then you
can add access holes to them to allow you to get into them for nest
maintenance. If they need painting, then a touch up here and there
may be in order. Remember, the more you can do for your birds, the
larger the broods will be and the larger your colony will
grow.
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Woodside Gardens
The Registry of Nature Habitats
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