Dear Professor Birdbrain,

I am a bird watcher and was asked if the males live longer than the females. The questioner is a owner of Martin houses and in his seventh year of banding he noticed he only had males with the seven year old bands and only one of the six year old birds was a female. Thanks as my internet search hasn’t answered my query.

(signed)

The Birdwatcher

Dear Birdwatcher,

I am surprised that a bander would ask this question as most banders go through a lengthy process and learning process before they can legally band.  However, I will answer your question to the best of my knowledge.

First off, the numbers of martins are skewed in favor of more males than females.  This insures that every female gets an opportunity to breed.  If she loses a mate early in the breeding process, there are always extraneous males to step in and take the first mated male’s place.

And, also factor in that in Purple Martins, there are many physical stresses  placed upon them.  A real stress is their migration of many hundreds and even thousands of miles to and from various places in Brazil in South America and the most northern places in Manitoba each year.

For the fewer numbered females, an additional stress of reproduction complicates their health and well being.

So, it would seem (1) the natural skewing of martin numbers in favor of more males than females; (2) Purple Martin migration; and, (3) the female martin reproduction cycle are reasons your banding friend is finding more males and more older males than females.

(signed)

Professor Birdbrain