White-chins and chicks

November and December are always exciting times on Bird Island as many of our study species being to hatch. In mid-November the northern geeps began hatching, followed shortly by the gentoos.

A northern geep chick just pipping out of its egg!

Geep chick being brooded

Gentoo chicks

By the end of the month we were seeing ducklings running around, although pintail breeding times can be so variable we were also lucky enough to find a nest of eggs in December – a very rare sighting!

A pintail nest, only the second I have seen and the hardest nest to find on BI!

Then in December the skuas were hatching closely followed by the macs and mollies in the middle of the month. The final species to hatch at this time were the southern geeps at the end of the month.

Skua chick

Mac chick

It is great to see all the life around the island and whilst some species are faring better than others at this stage at least there are no breeding crashes like there was for the gentoos last season! Of course it is not just the birds that are progressing, the seal pups are growing up well and enjoying being left alone around the beaches by their mums who are going out to feed.

A puppy trying to investigate inside a log!

"Who are you? Intruding on our puppy party!"

They are very curious at this stage, and tough little guys!

Not all species are at the young stage though, the wanderers take so long to raise a chick that they don’t actually lay their eggs until mid-December and won’t hatch until March. Alongside this whilst most chicks have fledged there are still a few stranglers left by the end of the month and these won’t take their first flight until January, by which time all of this years’ eggs will have been laid! (This is why wanals only breed once every 2 years, they don’t have the time/energy to lay an egg and raise a chick so close after their previous chick has fledged.)

A wanal not yet quite ready to fledge

'Superhero wanal' - so called because of the mask look on the face - practicing to fly

But amongst all this excitement and regular studying of all these species this December marked a very special survey for us. Last year we had the all island giant petrel census, but this year we had the all island white-chinned petrel census!

White-chins are burrow nesting seabirds and are about the size of a magpie but shaped like an albatross! This breeding habit makes them more difficult to survey than giant petrels who could simply be counted every time one was seen. In fact counting a few thousand giant petrels above ground is much simpler than counting a few magnitudes more of underground white-chins! So a different method is required.

White-chins are hard to get photos of, so having to re-use a couple from a blog last year...

Instead of trying to count all burrows, a near impossible task that would take months, we instead set up quadrats in areas that represent the surrounding habitat and terrain and counted the number of burrows within the quadrat alone; therefore we don't actually have to count all burrows on the island, so long as we are representative of the island as a whole the numbers can be extrapolated. Each burrow is checked for occupancy in order to determine the ratio of active to inactive burrows.

...but when the photos are this good I can't help it!

Whilst using this quadrat method makes the survey feasible it is still a long-haul survey. We conducted 495 individual quadrats, representing the habitats across the entire island, across 12 days of work (15^th-24^th, 27^th and 31^st December). Usually a quadrat would take 4 people to survey, two taking measurements of the habitat (tussock height, seal presence, incline, orientation, tussock cover) with the other two counting and assessing burrows. Repeating this process 495 times takes a lot of effort but it was a lot of fun – except when sticking our heads in the tussock during hayfever season makes us suffer through some of it!

Measuring the habitat (Photo courtesy of Carrie)

This census was one of the biggest I have ever conducted and it went incredibly well, white-chins are potentially becoming my favourite species, their call is something I will always remember, particularly as it is the sound I go to sleep with – they are nesting in the tussock behind base as well – and they have a very striking look despite being almost all black. They can be quite curious birds and I am very happy to have worked so much with a species that is not usually studied this way (all island census’ for any species only occur every 5 or 10 years depending on the species, except wanals which are an annual survey).

A white-chin lands mid-survey...

...and just hangs around to see what we are doing! :)