Variación anual en la actividad de anidación y productividad de la cotorra serrana occidental (Rhynchopsitta pachyrhyncha)

Abstract

WE STUDIED ANNUAL VARIATION IN REPRODUCTIVE ACTIVITY AND PRODUCTIVITY OF THE THICK-BILLED PARROT (RHYNCHOPSITTA PACHYRHYNCHA) DURING A FIVE YEAR PERIOD (1997-2001), IN FIVE NESTING AREAS AT THE SIERRA MADRE OCCIDENTAL IN MEXICO. TWO BREEDING AREAS CONTINUE TO BE THE BREEDING STRONGHOLDS FOR THE SPECIES. WE DOCUMENTED 491 NESTING PAIRS AND DETERMINED THE OUTCOME OF 162 ACCESSIBLE NESTS. A NESTING PAIR LAID IN AVERAGE 2.7 EGGS, AND PRODUCED 1.6 FLEDLINGS PER EGG-LAYING PAIR. OVERALL NEST SUCCESS WAS 80% AND NOT SIGNIFICATIVE DIFFERENCES WERE OBSERVED IN NESTING SUCCESS AND PRODUCTIVITY AMONG AREAS WITH DIFFERENT CONSERVATION CONDITIONS AND FORESTRY MANAGEMENT REGIMES. HOWEVER, THE BESTPRESERVED NESTING AREAS CONCENTRATED A HIGH NUMBER OF NESTS. SOME YEARS THE SPECIES BREEDING ACTIVITY DECLINES DRASTICALLY AT REGIONAL SCALE AFFECTING SEVERAL NESTING AREAS.