RESEARCH AND CONSERVATION
The Hawk-Eagle Program
Neotropical raptors are in dire need of study as basic natural history information on the nests, eggs, home range, minimum area requirements, demographics and movements of over half are unknown (Cade 1989). The three hawk-eagle species (Black, Ornate, and Black and White) found throughout Central and South America are not common anywhere and there is a lack of baseline data to make proper management decisions for these species. In Belize all three of the hawk-eagles are resident and have yet to be studied.
Based on anecdotal record trends and taking into account their dwindling habitat the hawk-eagles are considered “species with dangerously low populations” (Clinton-Eitniear 1986). All three hawk-eagle species are listed as Least Concern by the IUCN, but the Black and White Hawk-Eagle was listed as Near Threatened from 1988 to 2000 (IUCN 2008). With insufficient baseline data we cannot properly assess present populations and make demographic predictions. The hawk-eagles could be more or less endangered than current estimations, so as we learn more about these species we can better quantify populations.
To date, The Peregrine Fund’s Maya Project, which took place in Tikal National Park, Guatemala during the late 1980’s and early 1990’s is one of the largest full scale studies conducted on Neotropical raptors. Of the three hawk-eagle species only the Ornate Hawk-Eagle has been studied extensively through nest surveys and radio-telemetry (Lyon and Kuhnigk 1985, Klein et. al. 1988, Flatten et. al. 1989, J. Madrid et. al. 1991, H. Madrid et. al. 1992). During the Maya Project three Black Hawk-Eagle nests were studied, which provided valuable information on nesting, diet and movement patterns, but not enough to make any population estimates (Funes et. al. 1992). Other than those located as part of the Maya Project only a few nests have been recorded throughout the Black Hawk-Eagle’s global range and only one study has been conducted on its home range and movement patterns (Smith 1970, Rangel-Salazar and Enriquez-Rocha 1993, Canuto 2008). The Black and White Hawk-Eagle is the least known of the three species and basic natural history information is lacking, including identification of juveniles and incubation periods. It has never been studied extensively and only two nests have been described outside of our Hawk-Eagle Program (Strauch 1975, Canuto 2008).
In 2009, the Belize Raptor Research Institute (BRRI) launched the Hawk-Eagle Program in Belize as an effort to better understand all three poorly known hawk-eagle species after preliminary observations were made between 2006-2008 on the feasibility. This minimum ten year program will focus on locating active nests of all three species of hawk-eagle, gaining information on nesting biology, home range size, movement patterns, habitat utilization, foraging ecology and understanding intraspecific and interspecific competition through nest monitoring and radio-telemetry. To date, BRRI with the help of local peoples and other organizations, have located seven active nests throughout Belize; one Black Hawk-Eagle (Spizaetus tyrannus); four Ornate Hawk-Eagle (Spizaetus ornatus); and two Black and White Hawk-Eagle (Spizaetus melanoleucus).
This minimum ten year program will determine nesting biology, movement patterns, food habits, home-ranges, habitat preference and minimum area requirements of all three hawk-eagles in Belize. With the data obtained from this study we can better manage hawk-eagle populations throughout their range.
Our goal is to study a minimum of two nests per species through an entire breeding cycle and radio-tag a minimum of four (2 males and 2 females) adults and two juveniles (1 male and 1 female) from each species. By radio-tagging these individuals we can determine habitat requirements for juveniles and adults, home-range, juvenile dispersal, and where juveniles are taking up residence after reaching adulthood and why they are choosing to reside in particular areas.
The Stygian Owl Project
The Stygian Owl, Asio stygius robustus, occurs patchily throughout the pine forest and pine savanna of Mexico and northern Central America where it is poorly known. The status of the Stygian Owl is considered Least Concern by the IUCN due to its large home range (Birdlife International 2009), but is probably threatened by deforestation of pine forest (Konig and Weick 2008). In Belize, it is considered Vulnerable due to it being prosecuted as a perceived pest (Meerman 2005). Its breeding biology, distribution and geographical variation are poorly known making this one of the least understood owls in the Neotropics. In Belize, the Stygian Owl is considered a rare resident throughout the pine belt, but there are few records due to its nocturnal and shy habits (Jones 2003). The largest population is located in Mountain Pine Ridge with a few records from the Belize Zoo and Hill Bank (pers. observ., Jones 2003).
This study will determine diet habits throughout the different seasons, relative density, habitat utilization, movement patterns, home-range and dispersal patterns of Stygian Owls. Stygian Owls are known to have high roost-site fidelity. At these roost sites is where they will regurgitate pellets (prey mass that can not be digested), so locating these roost sites is critical in the success of this project. To date, we have located at least 3 different pair’s roost sites and have found a total of 7 areas that have been or are being used as roost sites.
The objectives of this study are to locate a minimum of 3 adult pair’s roosting sites throughout the study area to compare seasonal diets, prey species, number of prey taken in each season, prey biomass, habitat preference, density, movement and home-range. With this data we can better determine diet, foraging habits, habitat preference, relative density, home-range, area requirements, movement patterns and the potential effects of deforestation or logging on Stygian Owl populations. In the future, the Stygian Owl in Belize could be a similar situation to the Spotted Owl in the United States, where they have dramatically declined due to heavy logging of the conifer forests, which they are specialists of. The Stygian Owl could be a good indicator species of the health of the pine forests throughout Mexico and Central America.
The Solitary Eagle Project
The Solitary Eagle, Harpyhaliaetus solitarius, has a patchy range from western Mexico to northwest Argentina where it is a rare and local resident throughout (Ferguson-Lees and Christie 2001). In Central America only a handful of confirmed records occur from the foothills and highlands of Mexico, Guatemala, Belize, Honduras, Costa Rica and Panama. It is currently classified as Near Threatened due to its moderately small population size, which is estimated to be between 250-999 individuals (Birdlife International 2009). Based on further evidence of population trends it may be up-listed to Vulnerable (Birdlife International 2009).
To date, only two Solitary Eagle nests have been discovered, which were found in Sonora, Mexico in 1947 and 1958. The nests were visited once and the adults were collected as museum specimens, so no detailed observations of breeding biology or description of the nests were conducted. Smith (1982) found what he identified as two Solitary Eagle nests in Oaxaca, Mexico, but was later identified as Common Black-Hawk nests (B. Clark pers. comm.). With identification between the two black-hawk species and the Solitary Eagle difficult, photo documentation or a very thorough description are the only acceptable records for this species. There have been many reports from Belize of Solitary Eagle, but the first well documented record occurred in 1997 in the Mountain Pine Ridge area by Steve Howell and the first photo documentation in 2004 in the Mountain Pine Ridge Forest Reserve by Chris Benesh (Jones et. al. 200). To date, there have been 11 records from Belize, outside of our observations, with all but two from the Mountain Pine Ridge area. Only five papers have been published on this species exemplifying the importance of any studies on this vulnerable species.
In 2008, the Belize Raptor Research Institute (BRRI) launched the Solitary Eagle Project in Belize as an effort to better understand this poorly known species, which is suffering from population declines for unknown reasons. This minimum five year project will be the first full scale study conducted on the species throughout its range and the first description of its nesting and breeding biology, movement patterns, food habits, home-range, area requirements and demographics. This study will aid in determining the status of the Solitary Eagle and will be the only model for other populations across its range.
The goal of this study is to locate a minimum of two active nests, in which then daily nest observations through an entire breeding cycle will be conducted. Once the nest is located at least one adult from each pair and the juveniles will be fitted with radio transmitters. By radio-tagging these individuals we can determine habitat requirements for juveniles and adults, home-range, juvenile dispersal, where juveniles are taking up residence after reaching adulthood and why they are choosing to reside in particular areas.