Marbled Murrelet diving ©Mike Danzenbaker
Marbled Murrelets are an interesting little bird, as many aspects of their life are unknown. One area that has received some recent attention is related to their foraging behaviour. As their primary food sources (fish and small crustaceans) tend to be dispersed over large areas (Muirhead et all 2013, Pontius,Kirchhoff 2009), they need efficient strategies to find food for themselves as well as for any offspring. One such strategy is using the presence of whales (specifically gray whales) as an indicator of food supply. This behaviour is likely linked to seasonal availability of food as well as the needs of the chick (Muirhead et all 2013).
Marbled Murrelets eat up to 28% of their body weight in a day, but they have the capacity to increase their food uptake during such times as breeding (Pointus , Kirchhoff 2009).
Marbled Murrelet at sea
photo credit Keven T. Karlson
When they are caring for young, the adults must factor in the additional cost of bringing food back to the baby. As they are efficient at catching their prey, they will invest more of their time into diving for food (Pontius, Kirchhoff 2009, Peery et all 2009). In order to do this, they increase the number of dives they do, rather than the length of each dive (Peery et all 2009).
Sources
Muirhead, K.A, et all. 2013. Marbled Murrelets ( Brachyramphus marmoratus) foraging with gray whales (Eschrichtius robustus) off Vancouver Island, British Columbia. Canadian Journal of Zoology, Vol.91 No.12 pp. 847-852
Peery, M. Zachariah et all. 2009. Meeting Reproductive Demands in a Dynamic Upwelling System: Foraging Strategies of a Pursuit-Diving Seabird, the Marbled Murrelet. The Condor Vol. 111 No.1. pp. 120-134
Pontius, Kira.E., Kirchhoff, Matthew .D. 2009. Prey-Capture by Marbled Murrelets in Southeast Alaska. Northwestern Naturalist Vo. 90 pp. 151-155
Images
Diving Marbled Murrelet – Mike Danzenbak http://www.avesphoto.com/website/WD/species/MURMAR-19.htm accessed Nov 2 2015
Keven T. Karlson http://kevinkarlsonphotography.com/gallery/v/seabirds/Marbled+Murrelet_+AK_+May.jpg.html accessed Nov 2
