San Francisco Bay NWR Complex
Pacific Southwest Region

The Murre Maniac
The Common Murre Project Update – June 2008

Growing up!

June is an eventful month for Devil’s Slide Rock. 300 to 600 murres attend the rock daily. Egg-laying has continued with over sixty eggs laid this month. In late June, eggs started to hatch. The first chick was seen on 22 June. Currently, there are 25 chicks on the rock, ranging from one to nine days old.

These young chicks must grow up quickly because at 23-24 days old, they will fledge. So, they have to eat a lot! One adult murre usually stays with the chick, while another forages for food. The foraging adult will then return with a prey item, usually dangling from its bill, to feed the chick. Devil’s Slide Rock murre chicks primarily eat fish, especially anchovies. Chicks are fed a single fish two to five times daily. The chick feeding rate can vary with the size of the prey, caloric value, availability and chick age. 1-2days-old chicks are fed two fish per day while 9-10 days-old chicks are fed 4-5 fish on average. When fish are difficult to find, the foraging parent have to spend more time hunting thus lowering daily feeding rate.

While murre chicks just started to hatch, other seabird chicks on Devil’s Slide Mainland have been growing for sometime. Many Brandt’s and Pelagic Cormorant chicks have started to grow their contour feathers, replacing their down feathers. Some of them are very active and close to fledging. Unlike murres, cormorant chicks do not eat their fish whole. They eat partially-digested fish that their parents regurgitate in small morsels. Western Gull chicks started to hatch mid-month. Their bodies are still mostly covered in down but few have started to grow contour feathers on their wings.

June 2008 Murre Counts on Devil’s Slide Rock

Date

# Murres

Date

#Murres

6/2

684

6/18

415

6/4

588

6/20

339

6/6

488

6/22

564

6/8

372

6/24

424

6/10

343

6/26

407

6/12

399

6/28

377

6/14

479

6/30

484

6/16

593

 

 

*Compiled by Deasy Lontoh 

Last updated: September 1, 2011