Patterns of Cavity-Entrance Orientation by Gilded Flickers (Colaptes chrysoides) in Cardón Cactus

We studied patterns of cavity placement and orientation by the Gilded Flicker (Colaptes chrysoides) in the card6n cactus (Pachycereus pringlei) of Mexico, a columnar cactus characterized by a complex branching pattern. Overall, Gilded Flicker cavity entrances were oriented significantly toward the north-northwest, and they tended to face away from the rest of the cactus structure. There were more cavities proportional to the number of arms in the northwest quadrant, and these cavities had the strongest tendency to be oriented to the northwest and to face away from other arms. Cavities in the northeast quadrant were ori- ented slightly east of north, maintaining a strong pattern of orientation away from other cactus arms. Southwest quadrant cavity orientations were similar to those in the northwest quadrant but deviated from the trend of facing directly away from the bulk of the cactus structure. The fewest cavities proportional to number of arms were in the southeast quad- rant, and these showed no significant orientations, instead having the greatest variation in directional orientation as well as orientation with respect to other cactus arms. Received 24 March 1997, accepted 20 June 1997.