Data from: Rock wrens preferentially use song types that improve long distance signal transmission during natural singing bouts

When animals are capable of producing variable signals they may preferentially use some signal types over others. Among songbirds, individuals are known to alter song type form and usage patterns in contest and mating situations, but studies have not examined how song choice improves signal efficacy during broadcast song. For this study we investigated rock wren Salpinctes obsoletus song type use rates during natural singing bouts. We tested three hypotheses for adaptive song use during broadcast song: 1) birds improve signal content by increasing the use of high quality songs, 2) birds optimize for signal propagation by preferentially using songs that transmit well, and 3) birds maintain energy by reducing the use of costly songs. The study included 19 058 songs sung by 12 individuals, each of which had a measured song repertoire of between 52 and 117 song types which were produced at highly variable rates. Results indicated that rock wrens did not preferentially sing song types with shorter durations or fewer frequency switches, as would be expected if they selected song types to minimize delivery costs. They also did not favor songs with more rapid trills or more frequency switches, as would be expected if they adjusted song use primarily to indicate quality. Focal birds did preferentially sing significantly longer songs with lower bandwidths, lower frequencies, and slower trill rates. Results suggest that natural broadcast singing patterns are shaped more by the benefits of long distance transmission than by the benefits of advertising performance ability or the costs of song production

A Year-long Study of Food consumption by Captive Whooping Cranes at the International Crane Foundation

Throughout 2002, we recorded daily food consumption by 12 pairs of captive whooping cranes (Grus americana). For 7 pairs we recorded food consumption throughout the entire year while there were large continuous gaps in measurements of food consumption for 5 pairs that raised chicks that year. Birds received both a maintenance and breeder diet, and for both we converted food consumption to energy intake (Joules/g body mass) using the combined fall weights of female and male. We compared daily energy intake with 6 meteorological variables (involving temperature, wind speed and humidity), photoperiod (natural and artificial) and egg laying using multiple regression. We found mean daily energy intake averaged 411.4 + 141.6 j/g body mass (+ SD, range: 20–1,202). Energy intake was lowest in June and July and highest in March (pre-laying), October and November (premigration and migration). In addition, we examined the signs of the coefficients for each environmental variable among all pairs (using sign tests). We found that daily energy intake was negatively correlated with daily mean temperature. Further, we found that daily energy intake was positively correlated with both daily minimum and daily maximum temperatures. These last 3 findings suggest that whooping cranes, like many other homeothermic animals, have a thermal neutral zone and that temperatures above and below the zone require energy expenditure to maintain regular body temperature

Rock Wren song data - Benedict and Warning JAB 2017

Spreadsheet containing song type measurement and use data for all song types sung by 12 individual rock wrens included in the study