(Aug/2015)

High Predation Rates at Black Skimmer Nesting Site - News from our INAU / Pantanal Waterbird Study Group

The fieldwork at the Rio Cuiaba nesting colony started with the onset of the reproductive period in the second half of July. At this time a total number of 104 individuals of three species were present (Black Skimmer, Rhynchps niger: 96; Large-billed Tern, Phaetusa simplex: 2; Yellow-billed Tern, Sternula superciliaris: 6). At the beginning of the study some of the 24 registered Black Skimmer nests with eggs were already abandoned, others were stepwise given up in the following weeks, but new ones still built. Until now 8 active Black Skimmer nests still exist. However of the 12 hatched offspring only 50% survived the first week, three weeks later only one was still alive. The Roadside Hawk (Buteo magnirostris) together with the Jabiru (Jabiru mycteria) account for the high loss of skimmer juveniles. Egg predation was observed only recently. Footprints around the nests together with eggshell remains indicate the Golden Tegu lizard (Tupinambus teguixin) as a major predator. The reproductive period of skimmers and terns at our Pantanal study site ends around beginning of October. We will keep you updated with more news on that issue by September.

Photo: Jabiru (Jabiru mycteria) predating on a Black Skimmer (Rhynchps niger) chick at the Rio Cuiaba study site.