To celebrate World Migratory Bird Day 2019, we’ve got an an update on royal albatross research from ranger Jim.
In 2018 the our team at Pukekura/Taiaroa Head, working with Bruce Robertson from the University of Otago, ran a trial to determine the feasibility of DNA sexing northern royal albatross chicks from DNA samples.
Without DNA, sex determination can be a tricky business. Male and female albatross chicks are hard to differentiate until approximately four months old, after which males start to outgrow females in both size and weight. Males tend to be more aggressive rather than submissive when approached. However, like all populations we experience crossover in measurements and behaviour and can have large females or small males and aggressive females and submissive males.
Management decisions during a breeding season are often based on the albatross chick’s sex. This can range from how much to supplementary feed if a chick is underweight or has lost a parent, to the size of the identification bands put on the legs before a chick fledges. By collecting a DNA sample just after hatching we can be certain of a chick’s sex within days rather than four months. This significantly improves our management decisions of the welfare of the chicks and their chances of survival into fledging.
The blood collection process is non-invasive to the chick as the rangers collect dried blood vessels left behind in the eggshell after hatching, as these blood vessels are the final part of hatching as they detach from the chicks. This is the same process used by DOC’s kakapo recovery programme to sex kakapo chicks. Bird blood is nucleated, meaning every red blood cell contains a copy of the genome which means you don’t need much blood in order to DNA sex a chick. For example, if fresh blood were being collected, only about 25-50uL (i.e. 0.025-0.050mL) of blood, which is half a glass capillary tube, is needed.
This year there are 29 northern royal albatross chicks at Pukekura/Taiaroa Head, 19 of those are female and 10 are male. The Royalcam chick is female.