Aerial surveillance by a generalist seed predator: food resource tracking by Meyer's parrotPoicephalus meyeriin the Okavango Delta, Botswana

Abstract

Abstract:As a proven food resource generalist, Meyer's parrot (Poicephalus meyeri) was expected to track the availability of all significant food resources in its diet over time. Here we recorded all feeding activity during 366 standardized road transects for correlation with an index of relative food resource abundance over 18 mo. As expected, Meyer's parrot made food resource decisions according to relative abundance at landscape level. Feeding activity on food resources available throughout the year (e.g. ripeKigelia africanafruit) or not visible from the air (e.g. unripeDiospyros lycoidesfruit), however, did not correlate significantly with fluctuations in their relative resource abundance. In addition, over 70% of all feeding bouts were in the high canopy and over 70% of all food items consumed formed bi-coloured displays. The influence of estimated protein and energy acquisition rates from different food resources was insignificant. Therefore, important selection criteria for utilization by Meyer's parrot include relative abundance and visibility from the air (i.e. food resources with the highest probability of encounter when dispersing from a central roost). Sensitivity to fluctuations in resource abundance at landscape level demonstrates the relative importance of maximizing net gain per unit foraging time by minimizing foraging flight distance.

Nutrients in fruits as determinants of resource tracking by birds

“…Over shorter time periods and distances, adjustments in animal abundance linked to changing patterns of resource availability may reflect food search decisions made across and within habitat patches (García & Ortiz‐Pulido , Saracco et al . , Boyes & Perrin ).…”

“…), herbivores (Searle et al . ), granivores (Renton , Boyes & Perrin ), nectarivores (Cartar , Cotton , Rothenwöhrer et al . ) and frugivores (Fleming , Borgmann et al .…”

“…Feinsinger 1980, Loiselle & Blake 1991, Blendinger & Ojeda 2001 and mammals (e.g. Guiti an & Munilla 2010, Searle et al 2010, and encompasses diverse trophic groups such as marine and terrestrial predators (Korpimaki 1994, Fauchald et al 2000, Mauritzen et al 2001, herbivores (Searle et al 2010), granivores (Renton 2001, Boyes & Perrin 2010, nectarivores (Cartar 2004, *Corresponding author. Email: blendinger@birdecology.com.ar Cotton 2007, Rothenw€ ohrer et al 2011) and frugivores (Fleming 1992, Borgmann et al 2004, Guiti an & Munilla 2010.…”

“…Animals may track resources with nomadic movements in unpredictable environments (Korpimaki 1994, Dean 1997 or migrate between seasonal ranges when resources vary predictably (Levey & Stiles 1992, Mauritzen et al 2001. Over shorter time periods and distances, adjustments in animal abundance linked to changing patterns of resource availability may reflect food search decisions made across and within habitat patches (Garc ıa & Ortiz-Pulido 2004, Saracco et al 2004, Boyes & Perrin 2010.…”

First record of roan antelope (Hippotragus equinus) feeding on the fruits of the sausage tree (Kigelia africana)

“…Consequently, not many animals are known to feed on these fruits. Meyer's Parrots ( Poicephalus meyeri ) utilize the ripe but dehydrating fruits, while still hanging from the trees, and often open the fruits to feed on the seeds (Roodt, ; Boyes & Perrin, ; Map Ives pers. comm.).…”