Nature Done Wright

Earlier this week, I recounted the story of a birder from Central Jersey who has a screech cam and a female owl sitting on eggs.   

   Overnight recently, the egg count went from four to three. 

   The birder was trying to figure out what had happened. The male was also spending a lot of time in the box — something that the male screecher living near me has not done — and the birder wondered if one of the adult owls had inadvertently broken an egg.

    To answer the question, I consulted two owlers with plenty of knowledge and first-hand screech experience.

    Their verdict: Theft by predator.

    Expert One was brief:  "I’m going to guess that what is happening is he has a predation problem … 1 egg missing and the male is in the box to help defend the nest."

    Expert Two was more expansive: "I rather doubt that by jumping into the nest box, the owls would accidentally damage the eggs. 

    "Look at their investment in all of this.  Rather, I would look to red squirrels, gray squirrels, weasels, or snakes as possible predators. 

    "The calcium (as well as the protein) in the eggs is an important factor for these animals, who are also trying to gear up for the breeding season. 

    "At least for the squirrels and weasels, they can only carry one egg at a time, so, in-and-out they go… probably in a matter of seconds….. as the female owl is present and there is the threat of injury to them (the squirrels, weasel, snake).   

    He also cautioned warned about future raids:  "The predators remember these boxes.  In Europe, it was found that some of the predators (martins) remembered, from year to year, where their ‘food boxes’ were, and made it a normal part of their visit schedule."

     The birder says that he has an inch-thick predator guard on the opening, but perhaps that’s not enough. Any other theories?