Sexual Dimorphism, Female-Female Pairs, and Test for Assortative Mating in Common Terns

  title={Sexual Dimorphism, Female-Female Pairs, and Test for Assortative Mating in Common Terns},
  author={Ian C. T. Nisbet and Eli S. Bridge and Patricia Szczys and Britt J. Heidinger},
Abstract We trapped 656 Common Terns (Sterna hirundo) and measured five body dimensions and body mass for each bird; 313 birds were of known age, and 229 were sexed by DNA. Males were larger than females in all five dimensions, but were smaller in body mass. Early-nesting birds were larger than late-nesting birds in all five dimensions: at least for wing length, this difference was related to both laying date and age. Head length (from back of skull to tip of bill) was the most useful measure… 

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