Question about wing entrapment...

[Guest]

We lost one asy female and one asy male last year due to wing entrapment in the round hole dividing the entry and nest compartments of a Coates house. This year we have been doing daily checks of the house and have made saves on two different occasions.

We have weather stripping on the inside around the crescent holes, and have not had any problems there, but neither of us understands the theory behind doing that. We were wondering if it would work the same for the round holes.

We would also appreciate any other ideas?

The fighting has been so much worse this year than in years past, and we've only seen one subbie so far.

[Scott D.- La]

Kelly, It comes down to fighting, anything can happen during those fights even on the interior round hole of the divider with that thin metal. You can try the stripping as it may help. Enlarging the hole would certainly work. If you are still concerned, remove the divider and replace it with a piece of 3/4 or 1 inch aluminum angle. This will re-support the floor of the house.

[Tim Mangan-Kansas]

Kelly:

Although wing entrapment does not happen as much with round holes, it can happen as it has been reported here on the forum. Anytime you have the narrow edges in the entrance hole or the hole to the nesting area in a double compartment cavity, there is a possibility for wing entrapment. By increasing the thickness of the edges in the openings, it greatly reduces the chances of the top of the wing, where it meets the body, of getting trapped.

Over the winter, I purchased a "Safe Haven" metal house and really like the divider to the nesting area they incorporated into the design. Instead of a round hole to get to the nesting area, there is a divider that goes from the top to the bottom of the cavity but it only goes halfway back. It is like only having half a wall separating the two chambers. I believe many of the martin houses could be modified with this arrangement thus helping eliminating the chances of wing entrapment on the inside of the compartment.

Tim

[Guest]

Thanks guys for the explanation and the ideas. We might look at the Safe Haven house for next year.

Their fighting is out of control!

[John Miller]

Kelly

I had this happen last year in an interior round hole in a Coates house -- it's on my to do list to add weather stripping -- I think on the inside (nesting chamber). As said, enlarging these holes to three inches wide might be the best solution ultimately. When I modified several Trios a few years ago, I started making the holes three inch in the divider wall, offset slightly.

I'm glad you have added weather stripping on the inside of your crescents -- my theory as to why it works, per your post: It creates an interior bumper guard, eliminating the flat plane hole, which martins would not find in nature. So when two martins are at the hole fighting, but mostly inside the compartment, it reduces the risk that one martin with its wings open slides one wing along the interior wall and the wing slips out. The bird is then hung and struggles, at worst then pulling the other wing out too, the body and head remaining inside. You have reduced this risk.

I always suggest the dense automotive universal weather stripping for durability, or the PMCA "wing protectors."

John M

[DAKdude]

I manage several colonies with a combined total of over 300 compartments and I have been lucky and only had wing entrapment once. (Knock on wood) The odd thing was that the wing entrapment happened in a wooden T-14! So it doesn't just happen in houses with thin entrance walls. The thick walls can help prevent entrapment but can't eliminate it. Wish we could.
James