Identification and breeding of yearling Piping Plovers

• Published in: Journal of field ornithology 2010-12, Vol.81 (4), p.383-391
• Main Authors: Gratto-Trevor, Cheri L., Goossen, J. Paul, Westworth, Sharilyn M.
• Format: Article
• Language: English
• Subjects: age of first breeding; Animal wings; AVIAN BEHAVIOR AND ECOLOGY; Aviculture; Bird banding; Bird nesting; Breeding; Charadrius melodus; feather wear; Feathers; Female animals; Male animals; Mating behavior; Saskatchewan; yearling identification; Yearlings
• ISSN: 0273-8570; 1557-9263
• DOI: 10.1111/j.1557-9263.2010.00294.x

Age of first breeding is an important life history trait. Many Piping Plovers (Charadrius melodus) do not breed as yearlings, but little information is available concerning the age of first breeding. From 2000 to 2006, we marked 991 chicks in three areas in Saskatchewan, Canada, and subsequently determined when 102 (49 females and 53 males) first bred. Females bred significantly earlier, on average, than males. More females (68%) bred as yearlings than did males (41%; P = 0.04), with most others first nesting when 2-yr old (29% of females and 50% of males). As expected from differences between the sexes in age of first breeding, younger females were more likely to pair with older males than were younger males with older females. Chicks that hatched early in the breeding season did not breed at an earlier age than those that hatched late in the year. Unlike older birds, juvenile Piping Plovers do not replace flight feathers during their first winter. As a result, 18 of 27 yearlings (67%) had worn outer primaries, whereas only one of 123 (1%) older birds had worn primaries. In addition, whereas 20 of 24 yearlings (83%) retained a few buff-tipped median coverts, none of 119 known older birds had such coverts. As a result, we were able to identify all yearlings by their worn primaries, buff-tipped median wing coverts, or both. Wing lengths of yearling Piping Plovers were 3% shorter than those of older birds, presumably due to wear. Because there is no evidence of differences in adult survival rates between the sexes and breeding habitat is available, we speculate that fewer yearling males than females breed because primary wear may reduce the ability of yearling males to perform aerial breeding displays. La edad de reproducción es un dato importante en la historia natural de un organismo. Muchos playeros (Charadrius melodus) no se reproducen a la edad de un año, pero hay poca información concerniente a este asunto. Del 2000 al 2006, marcamos 991 polluelos en tres áreas de Saskatchewan, Canadá, y subsiguientemente determinamos cuando 102 individuos (49 hembras y 53 machos) se reprodujeron por primera vez. En promedio, las hembras se reprodujeron significativamente más temprano que los machos. Un número mayor de hembras (68%), que de machos (41%; P = 0.04), se reprodujeron al año, aunque la mayoría de la reproducción ocurrió a los dos años (29% de las hembras y 50% de los machos). Como esperado, por las diferencias en la reproducción de individuos de ambos sexos