Not the Nice Sparrow

—We began our studies of House Sparrow (Passer domesticus) biparental care in the mid-1990s by applying the classic Margaret Morse Nice field technique of color-banding individuals. Over the ensuing summers, we slowly accumulated quantitative provisioning records for 100 broods, even as we commenced a series of experimental manipulations. Provisioning data showed parental fitness, as expressed by offspring recruitment into the local breeding population, to be shaped mainly by the adults’ ability to deliver enormous insect prey items. It also turned out that production of robust and competitive fledglings routinely involves losing one or more nestlings (brood reduction in 42% of 1,000 multi-chick families). Recruitment success was compensated for the death of an offspring if the subsequent reallocation of food enables surviving nest-mates to gain at least 2 g more before fledging. Video samples showed that parents of day 3 broods favored larger siblings, even though brood reduction typically occurs on ,day 4, suggesting that adults participate actively in promoting some offspring over others. The social dynamic affecting how parents work as a team during provisioning does not fit the pattern expected if partners negotiate actively with one another, but points more toward the likelihood of ‘‘sealed bids.’’ Specifically, experimental handicapping of individual parents (tail-weights and hormone implants) indicates partners operate quite independently during brood-rearing. We are now extending our experiments into the incubation phase, where parents are probably better-informed about partner activities, thus potentially able to adjust to fluctuating contributions. Finally, behavioral rules affecting food deliveries seem to differ for females and males. Females normally increase provisioning as the brood ages, but males do not. However, when broods received supplemental nutrients, males matched the female upsurge, accelerating their deliveries by 25%, showing they usually work well below capacity. Received 31 December 2009. Accepted 28 February 2010. Among the many contributions for which bird behaviorists are grateful to Margaret Morse Nice, her pioneering use of color bands is probably the most universal. Color-banding seems utterly fundamental to behavioral ornithologists today— a trifle really—but on 26 March 1928, one pink celluloid ring provided Mrs. Nice with a means of recognizing a particular male Song Sparrow (Melospiza melodia) near her Columbus, Ohio home. Soon she banded a second male with a green ring, thereby exposing consistent differences between the two in song, aggressiveness, etc. It is hard to overstate what a difference this innovation has made to behavioral field studies. Pausing to think about it, much that we take for granted today was not available to Margaret Nice. For example, well before today’s ornithological neophyte affixes any color bands, the step of identifying the local avifauna, or even finding out which birds live nearby, promotes a trip to the 1 Department of Zoology, 730 Van Vleet Oval, University of Oklahoma, Norman, OK 73019, USA. 2 Corresponding author; e-mail: [email protected]