Anatomical bases of sex- and size-related acoustic variation in herring gull alarm calls

The hypothesis that anatomical or physiological factors can constrain the production of vocalizations is supported by an increasing number of examples from a range of taxa, where acoustic variation is related to sex, body-size or condition. In this study, we combine anatomical and acoustic investigations in herring gulls Larus argentatus to 1) identify co-variation between sex, body size and the dimensions of the vocal apparatus and 2) test the possible effect of this co-variation on interindividual variation in the acoustics of alarm calls. We found that the vocal apparatus was sexually dimorphic, with males having longer trachea and bigger vibratile membranes than females. We also identified a relationship between the head–bill length – a secondary sexual trait – and the length of the trachea in males only. However, we failed to identify corresponding sex- and body-size related variation in the acoustic components of alarm calls. We suggest that this absence of a relationship between anatomical and acoustic dimensions may reflect the lack of biomechanical constraints exerted during the production of alarm calls, and that such relationships are more likely to be expressed in this species’ sexual calls, whose production is characterised by more pronounced, ritualised postures that are more likely to highlight inter-individual size variation

Flier for a concert featuring The Cramps, The Slickee Boys, and the premiere of \The Punk Rock Movie,\ May 29, 1980

Flier for an I.M.P. Productions concert featuring The Cramps, The Slickee Boys and the D.C. premiere of the film \The Punk Rock Movie\ at the Ontario Theatre on May 29, 1980 at 8 p.m. The event cost $8 and tickets were available at Yesterday and Today Records in Rockville, Maryland, Record and Tape Exchange in Arlington, Virginia, Choice Cuts in Tenley Mall, Ticketron outlets, Orpheus Records, Warner Theater Box Office, Variety Records in Montgomery Mall, and Discount Books and Records. The flier features a photograph of the Cramps.I.M.P. (It's My Party, Inc.) is the promotion group that operated the 9:30 Club, which opened the same year in 1980 at 930 F Street NW. This flier was the first I.M.P. show, booked at Ontario Theatre by Seth Hurwitz; The Cramps never showed up for the show and Tex Rubinowitz performed instea

Climate change and habitat heterogeneity drive a population increase in Common Buzzards Buteo buteo through effects on survival

Jonker R, Chakarov N, Krüger O. Climate change and habitat heterogeneity drive a population increase in Common Buzzards Buteo buteo through effects on survival. Ibis. 2014;156(1):97-106.The effect of changing climatic conditions on wild populations has been the subject of much recent research. Most attention has been on the direct effects of climate changes on species of lower trophic levels and on the negative consequences of climate change. However, a deeper understanding of how climate change affects apex predators is vital, as they are keystone species that have a disproportionate effect on ecosystems. Studying survival in an apex predator requires individual-based data from long-term studies and is complicated by the integration of climatic effects on lower trophic levels. Here we assess how climate affects the survival of the Common Buzzard Buteo buteo. We analysed the survival of 670 males and 669 females over the period 1989-2011, during which time our study population quadrupled. We used mark-recapture survival analysis of individual resightings of breeding adults to identify the environmental factors best explaining survival. A decrease in the North Atlantic Oscillation (NAO) index increased survival to an extent that largely explains the population increase. This might be caused by higher Common Vole Microtus arvalis survival in drier conditions and under snow cover. Buzzard survival appeared to increase more for males than for females, possibly due to the males' higher sensitivity to winter food availability resulting from their smaller body mass. However, we also found that the effect of NAO strongly depended on the area in which individuals lived, especially for females. This may have been caused by the recolonization of Eagle Owls Bubo bubo in some parts of our study area. This study suggests that climatic changes can have complex effects on species of higher trophic levels via an interaction with their prey