Meeting Abstract
129.3 Monday, Jan. 7 A hummingbird tongue in a shorebird head: Tuamoto sandpipers are nectar-feeders BURLE, M.H.; RICO-GUEVARA, A.; RUBEGA, M.A.*; LANK, D.; Simon Fraser University; University of Connecticut; University of Connecticut; Simon Fraser University margaret.rubega@uconn.edu
Nectarivory has evolved repeatedly, and avian lineages that have adapted to floral nectars as a food source exhibit convergence on characteristic modifications of the beak and tongue. The Tuamotu sandpiper (Prosobonia cancellata) is an endangered Scolopacid sandpiper endemic to the Tuamotu Archipelago in French Polynesia. We document here evidence that Tuamotu sandpipers are nectarivores, with adaptations of morphology, feeding mechanics, and behavior reflecting a commitment to nectarivory that is not merely facultative. Previous investigators (Pierce & Blanvillain 2004) noted that Tuamotu sandpipers visit flowers, but could not confirm that they were consuming nectar. Our field observations revealed that adult and juvenile Tuamotu sandpipers visit nectar-producing flowers of the shrub Scaevola taccada and the tree Cordia subcordata frequently, probing deep into corollas. Examination of specimens showed that their tongue tip is bifurcated, a morphological modification unknown from other charadriiforms, but common in known nectarivores (e.g., hummingbirds and sunbirds). The hyobranchial apparatus of Tuamoto sandpipers is also modified in a manner consistent with nectarivory, with epibranchials that are elongated in comparison to other scolopacid sandpipers. We used high-speed video (up to 240 f/s) to film free-living Tuamotu sandpipers feeding at flat-sided nectar feeders; our videos demonstrate that the birds use cyclic tongue protrusion to extract nectar; no other sandpiper is known to, or is likely to be able to, protrude its tongue as far past the bill tip as do Tuamotu Sandpipers. Collectively, these lines of evidence demonstrate conclusively that Tuamotu Sandpipers represent a previously unappreciated independent evolution of nectarivory in shorebirds.
