Translocation of Harpy Eagle (Harpia harpyja) (Linnaeus, 1758) nest.

Abstract

For most birds, the nest is only a temporary structure that cannot be reused, not even for the same breeding season (Aguilar and Marini, 2007 ). However, the practice of reusing the nests is a typical behavior of hawks. The aim of this note is to describe the procedures taken for translocating a Harpy Eagle ( Harpia harpyja Linnaeus, 1758) nest located in an arboreal specimen ( Dinizia excelsa) approximately 45 meters high found within the future right of way of an electric power transmission line in the municipality of Manaus, State of Manaus, Brazil. This species is under Near Threatened status according to the IUCN (2014). The breeding period for Harpy Eagles is usually coincident with the start of the rainy season, usually between April and May (Galetti and Carvalho Junior, 2000). The nests, measuring up to 2 m in diameter, are built by the breeding pair together using thick twigs, in trees 50-70m high emerging from the canopy (DelHoyo etal., 1994 ). Theposition chosen for the nest is usually the main branch of a tree at a height ranging from 25 to 35 meters (Piana, 2007). According to Alvarez-Cordero (1996) , each breeding pair is linked to a territory centred on the nests, enabling one to calculate the mean breeding area for a pair. Each breeding pair usually incubates 1 to 2 eggs per clutch in what is considered one of the longest bird reproductive cycles (Aparicio, 2002 ). Females are responsible for 97% of the incubation, and the usual reproductive success is 1 egg per clutch (Del Hoyo et al., 1994). In May, 2012, an active Harpy Eagle nest was spotted approximately 45 meters high atop a Dinizia excelsa tree at 60° 00’ 37.4939” W/ 2° 55’ 24.4053” S (WGS 84), in the municipality of Manaus (AM). A single hatchling was seen in the nest being fed by its parents in the course of the period of observations. Initial characterisation of the need for translocation was linked to the nest being located within the right of way of a future electric power transmission line. A total of 52 surveys were carried out to follow the hatchling’s development and further assess and ascertain the necessity for the translocation procedure, comparing risks and benefits to alternative managing approaches. Observations made in the period between May and August, 2012 attested the hatchling’s dependence on the nest. A concerted effort by the consultants responsible for the environmental management and the company in charge of the transmission line construction led to a 10 month suspension of construction activities in the area surrounding the nest, time enough to allow the hatchling to reach a developmental stage such that the bird could fly to adjacent areas. Starting in September, 2013, the young could fly to trees surrounding the nest up to an approximate distance of 50 m. From January, 2013 onward, the parent’s absence from the nest was also noticed, a natural behaviour believed to stimulate the young Harpy Eagle to forage on its own (Luis Fabio Silveira, personal orientation at the Zoological Museum, 2012). Surveys carried out in February, 2013 found the young still roosting on the arboreal specimen housing the nest. At about the same time, the progress of cable stringing activities led to confirmation of the need for removal of the nest-bearing tree. Experimental controlled disturbance procedures were carried out as a further test of the young Harpy Eagle’s dependence on the tree housing the nest. Theteam responsible for such activities employed loud shrill noise emissions next to the D. excelsa tree in an attempt to displace the young bird. After the procedure, displacements of up to 100 metres towards the surroundings have been detected, confirming the bird’s capacity to move around on its own. The final decision for the necessity of the translocation procedure was taken during the final stage of the aforementioned surveys, and took into consideration the fact that Harpy Eagle parents are loyal to nesting sites. Three arboreal specimens with heights similar to the tree originally housing the nest were considered as possible sites for translocation. The final decision favoured the tree nearest to its previous location, at 2° 55’ 21.8304” S/ 60° 00’ 35.4626” W (WGS 84). The translocation itself took place on March 14