Mai & Blakeman discuss bark in nest

Pale Male inserting strip of bark into nest--March 2, 2007
photo courtesy of http://www.palemale.com



Below, an exchange of letters between regular correspondent Mai Stewart and John Blakeman, our Ohio hawk expert.

Hi John,

As always, I've been extremely interested to read your recent comments on Marie's website, and also was pleased to see the pix of you -- so nice to put a face to a familiar name -- and to see Savannah, as well!

My question/comment today concerns all the RTs' bark activity -- the first thought that crossed my mind is that this is wonderful, because hopefully it means that they're filling all those cracks + crannies in the nest through which wind + cold air can penetrate, as there seems to be some agreement, or at least serious thought, that that has been the reason for the failure of the eggs past two years. Bark, being dense, would be perfect (I'd think) for filling those holes + giving a more solid construction + barrier against the cold.

What do you think? Is this a possiblity? I've been so encouraged to see this nest-refinement activity going on, that I've begun to have more hope for the eggs this year. What are your thoughts? As always, so many thanks for sharing your knowledge + ideas w/ us!

Best, Mai

Blakeman replies:

Mai,

I, too, am encouraged with the placement of the new lining material in the 927 nest. The nest looks a bit taller, also. The insertion of bark indicates, I believe, that the pair feels a need to stop air flow through the bottom of the nest. The bark itself won't actually do that very well, as air easily moves between the bark fragments. Bark doesn't make much of a hermetic seal.

But it provides a strong, dense base upon which the finer lining materials such as grass and leaves can added. They really stop the air flow and hold in the heat from the mother's naked brood patch. It's like the insulation of a good winter down coat. If the loose (lining) insulation sinks down into the sticks below, it doesn't serve its purpose well. The bark provides a solid base upon which the sitting hawk can tuck the loose lining around the eggs before she settles down into the nest.

So far, very encouraging.