HOMING PERFORMANCES OF ADULT AND IMMATURE DUNLINS CALIDRIS-ALPINA (AVES SCOLOPACIDAE) DISPLACED FROM THEIR WINTERING AREA

The existence of possible differences in homing performances between adult and juvenile Dunlins was investigated at the beginning of two wintering seasons, when 49 adults (1992) and 51 first-year birds (1993) were caught in the Lagoon of Venice and displaced to Cervia Salines. Both sites (133 km apart) are important winter resorts for the species at the Italian and Mediterranean level. In a previous season, a control series of 47 birds belonging to both age classes were caught and released at Cervia Salines. The patterns of return at the capture site by the displaced birds did not statistically differ between the two age groups and the estimated percentage of homed birds after 50 days in the Lagoon of Venice was similar to the resighting rate of control birds in Cervia. Juvenile Dunlins seem to have developed a wintering site attachment by early December, i.e. 1-2 months after their arrival on the wintering grounds.