North American Crane Working Group

 

Date of this Version

2001

Document Type

Article

Citation

Gálvez Aguilera, Xiomara, Alvarez, Vicent Berovides, and Rosales, José Rivera. Distribution, abundance, and reproduction of the Cuban sandhill crane (Grus canadensis nesiotes). In: Ellis, David H., ed., Proceedings of the Eighth North American Crane Workshop, 11–14 January 2000, Albuquerque, New Mexico (Seattle, Wash: North American Crane Working Group, 2001), p. 216.

Comments

Reproduced by permission of the North American Crane Working Group (NACWG).

Abstract

We discuss the distribution, abundance, and reproduction of the Cuban sandhill crane (Grus canadensis nesiotes). This is an overview of a 5-year study conducted by the National Organization for the Protection of Flora and Fauna of the Ministry of Agriculture for the Republic of Cuba and assisted by the International Crane Foundation and Brehm Fund. The distribution of this subspecies was determined by visiting potential sites and areas where this race has previously been reported. Nine new populations were found. This brings the total to 11 on the Isle of Cuba, 1 on Cayo Romano, and 2 on the Isle of Youth. Habitat characteristics and levels of human activities were studied for 5 populations. In all 5 cases, population declines have resulted from alteration of natural habitat (mainly wet savanna) for agricultural purposes. Adding to the decline at the local level has been illegal hunting. Abundance was determined for 4 populations of the Cuban sandhill crane on the Isle of Youth (IJ), Cienaga de Avila (CA), Cienaga de Zapara (CZ) and on northern and southern parts of Ciego de Avila (CA) province. Our estimates came from simultaneous large-scale counts at fixed stations for 2 days. Local residents and national and foreign experts participated in these counts. We found 100 to 170 individuals per population with a mean of 4 to 6 cranes per census site. At 2 sites (i.e., IJ and CZ), the cranes were very concentrated. From count data, habitat preferences were determined. The cranes' preference for geomorphology and substrate varied by site, but the most preferred relief category was seasonally flooded plains. The most preferred vegetation was natural savanna. Reproduction was studied only on the Isle of Youth. From 1995 to 1999, we monitored as many nests as possible. During the 5-year study, we recorded 41 breeding attempts. Of these, 28 clutches hatched. In the last 3 years of the study, 7 reproductive indices were calculated, all of which showed increasing trends, suggesting improved reproductive conditions for this population. For example, the percentage of nests that hatched at least 1 egg increased from 20.0% (1997) to 83.3% (1999). The percentage of nests that fledged young increased from 66.7% (1997) to 87.5% (1999). We attribute the improvement in reproduction largely to a change in habitat management (reducing fire breaks in the areas north and south of the reserve and decreasing human disturbance in the nesting area).