Hi,

The big news this week is that 4 murre chicks have hatched at the Yaquina Head colony!  The chicks are on lower Colony Rock (the small rock on the NE side of Colony Rock, just above tide line).  It does seem odd to be excited about 4 chicks out of 25,000+ pairs, but you take what you can get in a year like this.  This is the first time in the 14 years of murre research at Yaquina Head by us and Julia Parrish (1998-2002) where there has been essentially zero chick production at Yaquina Head.  Roy Lowe noted that this is also the first time in his over 30 years on the coast.  The rocks are desolate most mornings, and the Common Murres return to the water without being spooked by the presences of predators. It seems as though they are behaving in the same fashion as they were when first settling on the rocks in the late spring.   Although you will see groups of Common Murres roosting on the rocks, due to the timing of the season, additional egg laying will not occur.  We have seen a decline in the presence of predators like the Bald Eagles around Colony and Flat Top Rocks recently and in response more Common Murres have congregated in those areas during the past week.

The focus of our efforts for murres has shifted to obtaining prey item photos.  Even though adult murres are not feeding chicks, they are returning to the colony holding prey.  So far, the prey have been primarily smelt yet again this year.  Our last update sparked a lot of interesting discussion including observations of murre foraging on smelt in northern CA and southern OR.  The predominance of smelt in murre chick diets at Yaquina Head in recent years has been a bit of a concern to us.  Prior to 2010, murre chicks at Yaquina Head commonly had 1/3 or more sand lance and clupeids (herring/sardine) in the diets, but from 2010 on, diets have been dominated by smelt (primarily whitebait and surf smelt).  Reproductive success at Yaquina Head has plummeted during this time.  Not that foraging on (non-eulachon) smelt is bad, but the lack of other prey species like herring and sand lance is the concern.  It’s also important to consider differences in prey search and capture costs that vary by prey species.  There is no doubt that eagle predation has been the dominant driver of egg and chick mortality at Yaquina Head since 2010, but we are not yet ready to discount other mechanisms working in the background, such as ecosystem impacts of potential food limitations for murres or alternative prey for eagles.   

On a more positive note, Cormorants have been relatively more successful. The Brandt’s Cormorant plots on Whaleback Rocks, North End of Colony Rock, Lower Colony Rock, and Lion’s Head Rock all have multiple nests with chicks, with the majority of nests having more than one chick. We have already witnessed fledging of chicks of at least one Brandt’s Cormorant nest on Lion’s Head. Brandt’s Cormorants have been affected less by Bald Eagles. Not so for Pelagic Cormorants.  Of the only 8 Pelagic Cormorant nests found in Smuggler’s Cove this year, are all empty as of 2 weeks ago. The Pelagic Cormorants have had a harder time this year at Yaquina Head.

This year we also had a remote camera set-up on the headland viewing Flat Top to obtain higher resolution prey photos during the breeding season.  The photographs are spaced five minutes apart during daylight hours, and the camera has been taking photos since mid-April. It also has given us data on disturbance events that are outside of our regular observations hours.

Thanks for your interest! 

The Yaquina Head seabird crew,

Carlos Lerma

Oscar Garzon

Ian Throckmorton

Stephanie Loredo

Jessica Porquez

Amanda Gladics

Rob Suryan