Oviposition Lag in Nazca Boobies <i>Sula granti</i>

Egg formation in well-studied poultry includes rapid yolk deposition (RYD), which completes the formation of the ovum, then ovulation and uptake of the ovum by the oviduct to complete egg formation. Roughly a day passes between the end of RYD and oviposition in these species. In other species, notably seabirds, egg formation is paused at the end of RYD for days or even more than a week. The phylogenetic coverage of data on this “oviposition lag” is patchy. We present the first estimate of oviposition lag for the Sulidae (4 d) and only the second estimate for the Suliformes.