Breeding decisions of Kittlitz's Murrelets, Brachyramphus brevirostris, Icy Bay, Alaska
The Kittlitz's Murrelet (Brachyramphus brevirostris) is an uncommon, dispersed-nesting seabird endemic to coastal waters of Alaska and eastern Russia. While the range-wide status of this species is unclear, proximate concerns regarding its viability are driven by low breeding propensity and nesting success. We studied individual and environmental factors associated with the decision to breed and timing of nest initiation of Kittlitz's Murrelets in Icy Bay, Alaska, over a 6-year period between 2007 and 2012. We radio-tagged 191 of 569 individuals captured during the spring pre-breeding period. At the time of capture, nearly all murrelets were exhibiting signs of breeding; most were in alternate plumage, paired, in apparently good body condition, and developing a brood patch. Yet an average of only 20% (range 5%-45%) of the radio-tagged murrelets nested annually. More individuals chose to breed during years with an intense Aleutian low-pressure system (i.e., low North Pacific Index) and low average wind speeds in the spring, with such conditions apparently leading to an earlier and stronger phytoplankton bloom. Our results also indicated a weak, positive association between the peak magnitude of chlorophyll-a and delayed nest initiation. While we infer that the decision to breed and timing of nest initiation are related in part to factors that reflect spring bloom dynamics, we encourage more directed studies on the relationship between environmental conditions during the spring pre-breeding period and the chronically low reproductive output exhibited by this species.
Kissling, M., S. B. Lewis, P. M. Lukacs, J. Waite, and S. M. Gende. 2016. Breeding decisions of the Kittlitz’s murrelets, Brachyamphus brevirostris, Icy Bay, Alaska. Marine Ornithology 44: 171-182.