An experimental census method and estimates of population density of a black howler monkey (<i>Alouatta pigra</i>) highland population in the Sierra Yalijux, Guatemala

Abstract

&#x0D; &#x0D; &#x0D; Groups of the Guatemalan black howler monkey (Alouatta pigra) in a fragmented northern Guatemalan cloud forest in the Sierra Yalijux were analyzed for group composition and size using an ornithological census technique. Audio and visual records were combined to estimate each group’s home range size. The 361 observations in 2002 estimated 50 individuals in seven groups. Two home range classes were observed with ≤ 1.87 ha and ≥ 2.87 ha. Compared to other recent studies, the density of A. pigra in the Sierra Yalijux is considerably higher than in other areas (83.3/km2 vs. 15.1/km2 in Quintana Roo and 23.0/km2 in Palenque) but about half the density found in Belize (178/km2). We discuss the relevance of the ornithology assessment method for howler monkeys.&#x0D; &#x0D; &#x0D;

Population Study of Coiba Howler Monkeys (Alouatta CoibensisCoibensis) and Coiba Capuchin Monkeys (Cebus Capucinus Imitator), Coiba Island National Park, Republic of Panama

“…Pre-established straight transects were walked each at morning between 06:30 to 12:30 hrs, and 14:00-18:00 hrs, and all sightings of primates and any vocalization activities at any time during these periods were recorded [20]. Coiba Island was visited once per month for a three-month period between May and July 2009 with a total effort of 850 survey hrs per 30 day survey.…”

Does population increase equate to conservation success? Forest fragmentation and conservation of the black howler monkey

“…Initial concern for the black howler monkey was stimulated by Smith (1970: 365), who suggested they prefer "extensive, undisturbed and mesic tropical forest" and were thought to be found primarily in low altitude areas that are below 1,000 ft (300m) above msl. However, more recent data suggest A. pigra also occur in high altitude areas (Baumgarten & Williamson 2007;Renner et al 2007) and inhabit a wider range of evergreen and semi-evergreen forests, including disturbed and riparian forests (Horwich & Lyon 1990;Crockett 1997;Silver et al 1998). In fact, Marsh (1999) regularly observed A. pigra using forest edges for feeding, travelling, resting, and howling.…”