Professor BirdBrain
03-07-2009, 12:29 PM
TELLING THE SY BIRDS APART/MALES FROM FEMALES
Are you able to clearly distinguish the immature (subadult)Purple Martin males from the Purple Martin females?
Just to help you.
Females do not sing the common song that we associate with Purple Martins; only males do.
The easiest indication is to watch the birds that appear as females for a moment and see which of the birds sing the very familiar martin churbling song which we know and associate with male martins. Females do not produce this song but a more "chu-chu-chuing" type of song.
As for coloration, immature males will have more black coloration like a dark collar, at their necks and faces. Their faces have what I have always called a dark batman look. While many immature males will have a very splotchy / black spotted breast, others will sport only "some" black feathers on their breasts. In fact, they could only have "one" black feather in this area and still be a male. There are many males that really, really look like females until they sing the male song. Then, it clicks for us. It's a male!
What is even more difficult for most except for the more experienced Purple Martin stewards is how to determine an ASY female from a SY female. First of all, we can eliminate all the males with complete black color and those subadult (SY=second year) males with the "black collar" or a black "batman" mask on their faces. All females are grey-breasted with the top of their breasts darker than the bottom area of the breast. Their backs are darker with the irredescent bluish black Purple Martin colaration but not solid black like adult males. The feathers underneath the tail, or rump area, are very light. This is the crissum area of the bird. In the immature females, the crissum area is very light--light gray.
There are many times when a landlord will tell me that they have many unattached females at their colony that are not nesting and breeding. The truth is that these "females" are really "unattached males," or bachelors (floaters, etc.) at the colony. It would be an uncommon occurrence for a female not to breed but as a matter of fact, no female goes "un-bred" at the colony during the season
The number of birds at the colony is skewed in favor of more males than females. So, all females get the opportunity to breed. If something happens to a breeding males in the early part of the martin season, another martin male may be able to step and breed again with the "martin widow."
Martin males "mate guard" their females to insure that she lays that particular male's eggs. There are many occasions when other unattached males (bachelors, the wanders, the troublemakers) of the colony will attempt to break the "pair bond" between a particular male and female bird. Many times, these birds can and do!
It has been shown by documentation and DNA studies with martins by Dr. Eugene S. Morton of the Smithsonian and National Zoo, that eggs of the immature martin males (SY=second year) are for the most part, actually fertilized by the mature males (ASY=after second year) of the colony!
There is certainly a lot of hanky panky going on at your martin colony site!!
I am sure that immature males return the following year with a different determination and breeding bird mindset. In addition to inexperience, this may also be why some immature males (SYs) do not make good parents. They instinctively realize in their little birdbrains that the eggs in the nests are not really their progeny.
For good information on Purple Martins, click this Cornel Lab of Ornithology site: http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Purple (http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/PurpleMartin.html)Martin.html (http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/PurpleMartin.html)
Any questions?
Are you able to clearly distinguish the immature (subadult)Purple Martin males from the Purple Martin females?
Just to help you.
Females do not sing the common song that we associate with Purple Martins; only males do.
The easiest indication is to watch the birds that appear as females for a moment and see which of the birds sing the very familiar martin churbling song which we know and associate with male martins. Females do not produce this song but a more "chu-chu-chuing" type of song.
As for coloration, immature males will have more black coloration like a dark collar, at their necks and faces. Their faces have what I have always called a dark batman look. While many immature males will have a very splotchy / black spotted breast, others will sport only "some" black feathers on their breasts. In fact, they could only have "one" black feather in this area and still be a male. There are many males that really, really look like females until they sing the male song. Then, it clicks for us. It's a male!
What is even more difficult for most except for the more experienced Purple Martin stewards is how to determine an ASY female from a SY female. First of all, we can eliminate all the males with complete black color and those subadult (SY=second year) males with the "black collar" or a black "batman" mask on their faces. All females are grey-breasted with the top of their breasts darker than the bottom area of the breast. Their backs are darker with the irredescent bluish black Purple Martin colaration but not solid black like adult males. The feathers underneath the tail, or rump area, are very light. This is the crissum area of the bird. In the immature females, the crissum area is very light--light gray.
There are many times when a landlord will tell me that they have many unattached females at their colony that are not nesting and breeding. The truth is that these "females" are really "unattached males," or bachelors (floaters, etc.) at the colony. It would be an uncommon occurrence for a female not to breed but as a matter of fact, no female goes "un-bred" at the colony during the season
The number of birds at the colony is skewed in favor of more males than females. So, all females get the opportunity to breed. If something happens to a breeding males in the early part of the martin season, another martin male may be able to step and breed again with the "martin widow."
Martin males "mate guard" their females to insure that she lays that particular male's eggs. There are many occasions when other unattached males (bachelors, the wanders, the troublemakers) of the colony will attempt to break the "pair bond" between a particular male and female bird. Many times, these birds can and do!
It has been shown by documentation and DNA studies with martins by Dr. Eugene S. Morton of the Smithsonian and National Zoo, that eggs of the immature martin males (SY=second year) are for the most part, actually fertilized by the mature males (ASY=after second year) of the colony!
There is certainly a lot of hanky panky going on at your martin colony site!!
I am sure that immature males return the following year with a different determination and breeding bird mindset. In addition to inexperience, this may also be why some immature males (SYs) do not make good parents. They instinctively realize in their little birdbrains that the eggs in the nests are not really their progeny.
For good information on Purple Martins, click this Cornel Lab of Ornithology site: http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Purple (http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/PurpleMartin.html)Martin.html (http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/PurpleMartin.html)
Any questions?