In most Neotropical Psittacidae the existence and extension of long-distance movements are poorly understood. The Blue-and-yellow Macaw (BYM; Ara ararauna) has a wide range in South America and its occurrence seems to be seasonal or sporadic in some areas. This study describes the results of BYM data collected in a monthly regular field effort from July 2001 to June 2005 at the RPPN SESC Pantanal reserve (Mato Grosso state, Brazil). The aim of the study was to evaluate the BYM's use of the reserve resources, its displacements and possible causes. Every observed BYM flock or individual had its date, hour, geographic coordinates, flock size, and activity (landed, feeding, or displacement) registered. The flight azimuth of continuous and straight displacements was also registered. We used circular statistics and vector pairs (azimuth and flock size) to analyze the observed intraday, monthly, and yearly displacements pattern. A total of 189 flocks and 854 BYM were recorded, the average size being 4.5 ± 3.7 individuals per flock. The prevalent activity category was displacement (85.2 ± 3.8%) and the flocks occurred with non-uniform distribution through the year. Seventy one percent of all flocks were registered in only 4 months, each one with a statistically significant well-defined flight bearing direction pattern. The mean vector angles calculated for the January/February data (279°/288°) were the opposite of those obtained for the May/June data (98°/110°). The intraday data showed no change in the main flight direction pattern when morning and afternoon data were compared, indicating they were not night roosting/feeding areas movements. The same months through the 4 analyzed annual cycles had the majority of the records. This directional and repetitive pattern does not fit in circadian or nomadic displacements, but suggests seasonal movements of the BYM in the studied area. The observed directions, period, and seasonal direction change of flight paths are consistent with pre- and post-reproductive periods observed in the central region of Brazil. However, still unknown is their origin and destination, as well as the involved mechanisms.
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