Good evening from the warm and still Eastern Shore. None of us who follow Tom and Audrey are very happy tonight, and for good reason. I won’t rehash what has been happening for the last couple of days in the nest, but will refer you to our blog posted on May 7, the title of which warned of some sad content. We fear the situation described in that blog will be the outcome of the current events happening in the nest. Most of you have not had to witness such a melancholy event in nature, and be warned, it will not be easy. Intervention is not an option, nature will have to take its course. Dr. Spitzer has provided his insight concerning Osprey Population Regulation, which we will share with you very soon. In the meantime, here is a portion of emails sent to the Conservancy from Dr. Spitzer earlier today:
I was just watching the osprey cam, as the male delivered part of a menhaden (black gut cavity visible, then yellow forked tail). There was a wave of nestling aggression, and the little third-hatch got clobbered when he dared to lift his head. Then feeding ensued: For big #1 and #2. The female ignored #3’s begging, and ate quite a bit herself.
Now #1 and #2 ate lying somewhat sated. #3 is separate, far side of the unhatched egg, with no sign of food in the crop, lying quiescent. Some fish does remain, and the male left after the delivery.
Stay tuned, PAUL
This is normal “brood size reduction” behavior in the face of food limitations and male foraging skills. Sometimes it’s called “Cainism”, after the Bible story–and you can see why! Though very hard to watch (for me too–and I’ve been a biologist for 45 years) it is one of nature’s ways of bringing animals into balance with resources. It’s found in a diverse array of carnivorous birds, including boobies in the Galapagos, and gorgeous Whooping Cranes on their remaining far northern Canadian breeding ground. In pre-European times, whooping cranes bred as far south as rich Wisconsin marsh habitat. With their slow maturity and feeble reproductive rate, only a remnant survived hunting, in the far northern wilderness portion of their migratory range. That region may be marginal foodwise; thus they often only bring one young south to Texas (from two hatched eggs). Some seabirds that are food-limited, such as albatrosses and petrels, have evolved a one-egg clutch. Chicks of the big albatrosses take many months to grow and fly, and the adults only breed every other year. They too are protected by their oceanic island and the wilderness of the sea, so that low slow reproduction is adequate.
I discuss Osprey Population Regulation in detail in OSPREYS EXPLAINED #5 [which will be posted on this blog soon]. I thought it was so important that I wrote my Ph.D. thesis on it, with ten years of field work. Please Note that to this day, the formerly 300-nest-strong osprey colony on Gardiners Is., NY, struggles to maintain 20 nests, with rampant nestling starvation. There one sees brood reduction to ZERO, and many/most successful nests fledge only one. That is partly because we have so drastically overharvested the Atlantic menhaden: This island is surrounded by many miles of prime menhaden habitat, Gardiners was a “menhaden colony”.
We do have some answers and thoughts in regard to some of the other questions/comments on Facebook. Not really in the mood to write any more tonight, so until the next blog, we remain:
Crazy Osprey Man and Mrs. Crazy Osprey Man