TY - CHAP

T1 - A protocol to allow density estimation and monitoring of the heavily traded grey parrots across their huge African ranges

AU - Marsden, Stuart J.

AU - Loqueh, Emmanuel

AU - Takuo, Jean Michel

AU - Hart, John A.

AU - Abani, Robert

AU - Ahon, Dibié Bernard

AU - Showers, Charles

AU - Annorbah, Nathaniel

AU - Johnson, Robin

AU - Valle, Simon

PY - 2013

Y1 - 2013

N2 - Estimating population sizes in the heavily-traded Grey Parrot would provide invaluable insights into sustainability of harvests. However, the species’ huge range, current rarity, variable abundance, cryptic habits, mobility, along with difficulty of logistics and lack of resources may present insurmountable obstacles to its effective study. This project piloted candidate survey methods (line transect distance sampling, encounter rates, road surveys, occupancy based on interviews) across five west and central African countries in an attempt to devise appropriate and robust methods for density estimation. Parrot density estimates were calculated for two protected areas in Cameroon, one key forest in Liberia, one in DRC and several areas of Côte d’Ivoire. Density estimates were highly variable across sites - ranging from < 0.5 per sq. km in Côte d’Ivoire and the site in DRC to over 30 per sq. km in Lobéké NP in Cameroon. Most significantly, we were able to define the relationship between absolute density estimates from distance sampling and simple encounter rates derived from casual forays in the forest. We argue that the relationship is especially useful in low density areas where distance sampling may never be feasible. Results also indicated that encounter rates of one group per day or more of searching are likely to indicate population densities lower than one bird per sq. km - a rarity that almost certainly should disallow bird harvest. An application would be for local park rangers to record a simple metric of number of groups recorded in a day’s activities in the forest (anti-poaching patrols) which would then be used to estimate ‘ballpark’ density estimates for the area. The relationship also forms a link between the anecdotal records of birders and nonornithologist researchers and density estimates.

AB - Estimating population sizes in the heavily-traded Grey Parrot would provide invaluable insights into sustainability of harvests. However, the species’ huge range, current rarity, variable abundance, cryptic habits, mobility, along with difficulty of logistics and lack of resources may present insurmountable obstacles to its effective study. This project piloted candidate survey methods (line transect distance sampling, encounter rates, road surveys, occupancy based on interviews) across five west and central African countries in an attempt to devise appropriate and robust methods for density estimation. Parrot density estimates were calculated for two protected areas in Cameroon, one key forest in Liberia, one in DRC and several areas of Côte d’Ivoire. Density estimates were highly variable across sites - ranging from < 0.5 per sq. km in Côte d’Ivoire and the site in DRC to over 30 per sq. km in Lobéké NP in Cameroon. Most significantly, we were able to define the relationship between absolute density estimates from distance sampling and simple encounter rates derived from casual forays in the forest. We argue that the relationship is especially useful in low density areas where distance sampling may never be feasible. Results also indicated that encounter rates of one group per day or more of searching are likely to indicate population densities lower than one bird per sq. km - a rarity that almost certainly should disallow bird harvest. An application would be for local park rangers to record a simple metric of number of groups recorded in a day’s activities in the forest (anti-poaching patrols) which would then be used to estimate ‘ballpark’ density estimates for the area. The relationship also forms a link between the anecdotal records of birders and nonornithologist researchers and density estimates.

M3 - Chapter

SP - 1

EP - 18

BT - Strengthening Capacity for Monitoring and Regulation of International Trade of African Grey Parrot

A2 - CITES Secretariat, null

PB - CITES Secretariat

ER -