Long-term monitoring of a hyacinth macaw Anodorhynchus hyacinthinus (Psittacidae) roost in the Pantanal, Brazil

Abstract

The hyacinth macaw Anodorhynchus hyacinthinus is the world’s largest parrot species and is currently listed as Vulnerable by the IUCN. This species commonly flocks in collective roost sites. We monitored a group of hyacinth macaws that has used a single roost site on a ranch with traditional, extensive cattle management in the Pantanal, Brazil, for over 50 yr. We analyzed 15 yr of monitoring data on the use of this roost site. We used simultaneous counts (n = 37), where individuals flying to the roost site were counted, and also counted pairs in nests. The results indicate that in 2001 there were 234 (mean no. of ind.; 95% CI = 55) macaws in the roost; 15 yr later 708 (95% CI = 142) were registered. The highest number of macaws registered was in the years of 2013 and 2015, when >1000 ind. were observed at the ranch. The model showed an increase rate of 26 ind. yr-1 over the 15 yr monitoring period. Temporal and seasonal fluctuations were observed, with the highest number of macaws recorded during rainy and non-breeding seasons. We discuss these results with an emphasis on the type of ranch management that favors the maintenance of hyacinth macaw food resources. The type of traditional cattle management used at the study site benefits both cattle production and macaw conservation due to positive interactions between cattle feeding habits and landscape-level management practices that preserve macaw habitat.