San Francisco Bay NWR Complex
Pacific Southwest Region

The Murre Maniac
The Common Murre Project Update May 2008

Peak Egg-laying Period!

Common Murre on NestDuring the month of May, the Common Murres residing on Devil’s Slide Rock and on the Mainland have been busy laying eggs! Common Murres lay one relatively large egg on their territory. Once the egg is laid, one of the pair always attends the territory to incubate the egg. When a bird is in incubating position, its body looks rounded and its back is arched. The wings are often relaxed and touching the ground to surround or protect the egg. Hours later, the mate that has been out-to-sea returns to the site to take its turn at incubating the egg. The pair switch spots with care so that the gg does not roll to a different site or off the rock! If an egg rolled off site, a murre will carefully roll it back to the appropriate spot using its bill and body. Murres will continue incubating their egg for 30 days at which time, a chick will emerge!

By the end of the month, we were monitoring 200 sites on DSR, 29 of which had retained their eggs. On the Mainland, there were 109 sites and 10 eggs. The eggs we have seen varied in color, from a light white, blue or green to an intense teal or turquoise! The eggs also have a variety of patterns from speckled or swirled with black markings to plain ones.

Common Murre on Nest
USFWS Photo

We have yet to see any Brandt’s Cormorant chicks, but there are quite a few nests with eggs on the Mainland. We are expecting to see their chicks by the second week of June!

 

May 2008 Colony Counts of Devil’s Slide Rock
Date
# Murres
Date
# Murres
May 1
555
May 15
662
May 3
798
May 17
427
May 5
796
May 19
510
May 7
603
May 21
267
May 9
735
May 23
231
May 11
961
May 27
427
May 13
522
May 31
647

* Compiled by Erica Donnelly

Last updated: September 1, 2011