The foraging ecology of red deer (Cervus elaphus) in a Mediterranean environment: is a larger body size advantageous?

In Mediterranean environments browse, is expected to be a major component o r the diet of red deer Cervus elaphus during the summer when most grasses s enesce. III this Study the hypothesis is tested that, if browse is an essen tial food resource at this time, the sex with the larger body size may have a greater physical ability to reach the tree canopy and include a higher p roportion of browse in its diet. The organic matter digestibility (OMD) and composition of the diet of a Population of red deer males and females were measured between July and September, in 1996 and 1997, in an area of Portu gal with a Mediterranean type of climate, using the n-alkane technique. Dir ect observations or animals browsing on tree canopies and shrubs were made also during the same period. The OMD of the diet was significantly differen t between sexes and between years and was higher in males than females both in 1996 (means +/- SEM for males and females, 0.65 and 0.58 +/- 0.026, res pectively) and 1997 (means for males and females, 0.59 and 0.48 +/- 0.045, respectively). The proportion of cork oak Quercus suber in the diet was als o significantly different between sexes and between years, with males havin g a higher proportion of cork oak in their diets in 1996 (males and females , 0.30 and 0.16 +/- 0.037, respectively) and 1997 (males and females, 0.41 and 0.23 +/- 0.064, respectively). A significantly lower proportion of the herbage layer was found in the diet of males in 1996 (males and females, 0. 46 and 0.64 +/- 0.048) but not in 1997 The number of observations or males browsing on tree canopies was significantly higher than females. It is conc luded that there are differences between sexes in the composition and quali ty of the diet and that a larger body size may confer advantages in situati ons where browse is an essential food resource.