Saturday, August 6, 2011

Purple Martins--Nesting Behavior

It is always amazing to me when a bird hangs in there, remaining on the nest while a nest-check is taking place.   
One of the tasks of a purple martin landlord is checking the nests to record progress or problems as they look after the welfare of their purple martin colony.  On one of my visits this summer to a martin colony in my area, I had the pleasure of being present for one of these nest checks.  Not only was it intriguing to see the array of twigs, leaves and other items the martins add to their nests, but also to see the several martin females that remained on their nests while the nest check was in progress.  Keep in mind, the rows of artificial gourd housing are lowered with a pulley-like system, so the bird is not only remaining on the nest through this lowering process, but through other nest checks until the portal in her gourd is finally opened for viewing.     
Personally, I call that courage.  But it is also true, that when landlords visit their birds on a regular basis, the birds become familiar with the landlord and are not alarmed when nest checks take place.  The purple martin's historical reliance on housing provided by humans and preference for the safety of living near human activity, may also help foster this trust.
In my last post I showed you a purple martin female trying to maneuver a long twig into her nest cavity.  Now, take a look at the pine cone in the nest above, and the image below.  The cone was almost the size of my hand, clearly larger than the smaller, more oblong cavity opening that it was maneuvered through.  
One has to wonder how a martin managed to grip an object this size, let alone, pull it into the nest cavity with an opening no larger than the one shown below!  
And then there's the leaves.      
A universal habit of purple martins is the addition of fresh green leaves to the nest, beginning with the completion of the loose nest structure and continuing until the eggs hatch.  Both the male and female participate in this activity, but observations seem to indicate that males become more preoccupied with this task. 
Above, you see a female martin plucking a maple leaf, and below, a male martin perched with a pear leaf before taking it into the nest. 
A report on the Purple Martin Conservation Association website gives some delightful descriptions of this leaf gathering activity (link provided below).  Practical theories for why fresh leaves are added to the nest include parasite control and thermal regulation, but the real purpose for adding the leaves remains a mystery. 
August 9th:  Update--Pine cones added by hand not beak!
Because the pine cones seen in the above nests did not make sense as nesting material, and one is quite large, I inquired about this occurrence at the Purple Martin Conservation Association, and also with the colony landlord.  Many purple martin landlords collect pine straw and place it in the nesting cavities prior to martin nesting activity to encourage nest selection.  Pine needles are often raked into a pile, and along with them, some pine cones.  When grabbing a handful of straw to place in a nest through the opened portal, sometimes a cone that is not open won't be felt.  This is what the landlord believed happened, especially in the case of the larger pine cone.    

Coming up:  More fun stories about purple martins!

Links and Resources:
To see all my posts on this colony visit:  purple martins.  The most recent post will be first.

Visit my Purple Martin with Prey painting and watch it take shape at Vickie's Sketchbook.

5 comments:

  1. I can't imagine PMs taking a whole pine cone into their nest. I wonder why??? I can imagine them picking them upwhen the cone is closed and getting it into the house but it would still be almost as heavy as the bird itself. Geez. Great pictures and narrative. I have been enjoying this entire series.

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  2. Purple Martins are amazing. They are starting to roost here on our state park getting ready for the migration south.

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  3. Wow~I knew they used leaves..didnt know about the pine cone..how the heck?? Great post and photos..and your art is lovely!

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  4. Love love love this and the photos! Gorgeous! Wouldn't it have been a treat to see that martin wrasslin' the cone into the gourd?

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  5. Thanks for your comments, everyone. I just added an update to the post about the pine cones. Seems there is a human hand involved. PUMA landlords sometimes add pine straw to the nest cavities prior to the martins nesting to give them some help and encouragement. And sometimes a pine cone can be hidden in that handful of straw without being noticed. The landlord was sure that is what happened in the case of the larger cone.

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