BELIZE RAPTOR RESEARCH INSTITUTE 2010 Annual Report The Hawk-Eagle Program & The Stygian Owl Project 10 May 2011 Submitted to: Belize Forest Department Submitted by: Ryan Phillips, Raptor Biologist Executive Director, Belize Raptor Research Institute BZ: Mountain Pine Ridge, Cayo District US: 1298 Hacienda Ave. Campbell, CA 95008 Belize Raptor Research Institute 2010 Annual Report Executive Summary In 2009, the Belize Raptor Research Institute initiated a long-term research program studying the three Spizaetus (hawk-eagle) species (Black, Ornate and Black-and-white) and the Stygian Owl, Asio stygius robustus, throughout Belize, focusing in Mountain Pine Ridge (MPR) and Rio Bravo Conservation and Management Area (RBCMA). Through these programs we will understand their status, population size, minimum area requirements, habitat preference and utilization, intraspecific and interspecific competition, breeding biology, movement patterns, diet, foraging habits, home range, and demographics. To date, the Hawk-Eagle Program is one of the largest full-scale studies conducted on the genus Spizaetus in the Neotropics, the other being The Peregrine Fund’s Maya Project in Guatemala, as well as the first long-term study on the rare Stygian Owl. During 2009 and 2010, 86 total observations of all three Spizaetus species were made in the MPR area, RBCMA, Chiquibul National Park, and Cerros, with 34 of Black Hawk-Eagle, 31 of Ornate Hawk-Eagle, and 21 of Black-and-white Hawk-Eagle. Of the 86 observations, 11 were in RBCMA, 6 in MPR, 39 in the transition zone from pine forest to broadleaf forest, 23 in Chiquibul, and 1 in Cerros. Five Spizaetus nests were monitored in 2010, 4 Ornate and 1 Black-and-white. Two new Ornate nests were located, one in RBCMA and the other near Cerros Archaeological Site in the Corozal District. All of the Ornate nests were active, whereas the Black-and-white was not. We studied the seasonal variation in the diet of the Stygian Owl in the Mountain Pine Ridge in Belize based on 194 prey items of 145 collected pellets at a single roost site from 3 March 2009- 26 February 2010. The sample included 61.9% birds, 19.1% bats, 12.4% beetles, 6.2% lizards, and .5% frogs. Of the total prey items, 31% were nocturnal species with 69% being diurnal. On average, February-May the diet consisted of 70% birds, where June-August were comprised of 37% birds, 32% bats, and 28% beetles and November- February consisted of 81% birds. The change in diet coincides with the emergence of beetles in June-August, and the influx of wintering migrant songbirds. According to biomass and quantity of prey items consumed passerines were the most important dietary component. In 2010, five roosting sites were located, where owls were seen frequently. Two of the five roosting sites were logged with the roosting tree cut down. Only one of the logged sites was any owl observed infrequently. This suggests that logging may have grave impacts on owl populations. In December, two male Stygian Owls from two different roosting sites were trapped and radio- tagged with VHF transmitters, which is the first time this species has been radio-tagged. 2 | P a g e Belize Raptor Research Institute 2010 Annual Report THE HAWK-EAGLE PROGRAM INTRODUCTION Neotropical raptors are in critical need of study as basic natural history information on the nests, eggs, home- range, area requirements, demographics, and movements of over half are unknown (Cade 1989, Bierregaard 1995, Bildstein et al. 1998). 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 were not studied prior to our research. Based on anecdotal record trends and taking into account Figure 1. Black Hawk-Eagle. their dwindling habitat and decreasing populations the hawk-eagles are considered “species with dangerously low populations” (Clinton-Eitniear 1986, Birdlife International 2009). All three hawk-eagle species are listed as Least Concern by the IUCN, but the Black-and-white Hawk-Eagle, Spizaetus melanoleucus (Fig. 2), was listed as Near Threatened from 1988 to 2000 (Birdlife International 2009). With insufficient baseline data, a proper assessment on present populations and demographic predictions can not be determined. 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 and conservation concerns. 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 the largest full-scale study conducted on Neotropical raptors. Of the three hawk-eagle species only the Ornate Hawk-Eagle, Spizaetus ornatus, 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, Spizaetus tyrannus (Fig. 1), 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 Figure 2. Black-and-white Hawk-Eagle, movement patterns (Smith 1970, Rangel-Salazar and Mountain Pine Ridge. Enriquez-Rocha 1993, Canuto 2008). The Black-and-white Hawk-Eagle is the least known of the three species and basic natural history information 3 | P a g e Belize Raptor Research Institute 2010 Annual Report is lacking, including incubation periods. It has never been studied extensively and only three nests have been described outside of our Hawk-Eagle Program (Strauch 1975, Anderson et. al 2004, Canuto 2008). In 2009, the Belize Raptor Research Institute (BRRI) launched the Belize Hawk-Eagle Program as an effort to better understand all three poorly known hawk-eagle species. 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, movement patterns, habitat utilization, foraging ecology, and understanding intraspecific and interspecific competition through nest monitoring and radio-telemetry. The goal is to study a minimum of two nests per species through an entire breeding cycle and Figure 3. Ornate Hawk-Eagle, RBCMA. 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. OBJECTIVES Locate and map hawk-eagle nests Determine breeding biology such as courting behaviors, nest construction, nest type and location, nesting season and dates, incubation length, clutch size, fledging time, nest success rate and dependency length of all three hawk-eagle species Determine diet and foraging habits of all three hawk-eagle species Record habitat usage and requirements of all three hawk-eagle species Determine home-range of both adult, juvenile and immature of all three species Determine if there is interspecific or intraspecific competition (competition exclusion) Determine prey base and density of prey Determine minimum area requirements for a viable population of each species Determine status and population sizes in Belize of all three species Determine minimum area to sustain all three species Educate and train locals and create awareness about hawk-eagles and raptor conservation 4 | P a g e Belize Raptor Research Institute 2010 Annual Report STUDY AREA This research was conducted within the Rio Bravo Conservation and Management Area (RBCMA), Mountain Pine Ridge Forest Reserve and surrounding private lands, which included Hidden Valley and the Headley property (Fig. 4). RBCMA is managed by the non-profit organization Programme for Belize and consists of over 260,000 acres of lowland broadleaf forest and wetlands. The Mountain Pine Ridge Forest Reserve (hereafter MPRFR) is managed by the Forest Department, in Belize’s Cayo District, and approximately 106,000 acres. The MPRFR is dominated by sub-montane pine forest and is the only locality in Belize with montane pine forest. MPRFR lies on the 17° North latitude at an elevation ranging from approximately 400-950 m with an annual rainfall of 2002 mm (Means 1997). Figure 4. Study Area, left: Mountain Pine ridge, right: Rio Bravo Conservation and Management Area. RESULTS In 2010, two new active Ornate Hawk-Eagle nests were located, one in RBCMA and the other near Cerros Archeological Site. We monitored a total of five hawk-eagle nests, four Ornate (Fig. 5) and 1 Black-and-white. Three Ornate nests were monitored in RBCMA, one near Cerros and the Black-and-white nest was located on the Hidden Valley private reserve. Figure 5. Ornate Hawk-Eagle nests monitored in 2010. 5 | P a g e Belize Raptor Research Institute 2010 Annual Report On 7 March 2010, one adult Black-and-white Hawk-Eagle was observed at the nest tree, which was the only occasion an individual was observed at the nest tree in 2010. Multiple observations were made throughout the year, but there was no activity at the nest. Measurements on the nest were taken as this is the 4th nest to be discovered of the species, so all data is critical in understanding their breeding biology. The nest was located in a large Ceiba, Ceiba pentandra, tree at an elevation of 381 meters in sub- montane moist broadleaf forest.