Growing Pins

It’s been a busy time here on The Rock this past month with the vast majority of eggs having now hatched. We’ve seen the eggs here tern from chick to fledgling in what seems like no time at all as we wardens have been scrambling to try keep up with the big peaks in synchronised laying and hatching that happen. The chicks go through dramatic changes here in a very short space of time (30 days). In this blog I wanted to try show how striking a transformation these birds make so quickly.

 This is the first chick hatched in a 3 egg clutch Common Tern clutch and we can also see it’s sibling has pipped a little hole in its egg and will be out soon (likely in the next 24hrs). This chick is around 1 day old, they’re more or less immobile for their first 1-2 days and it is nearing the point of taking it first few steps around the nest. When they emerge from their eggs they are wet, sorry looking creatures but soon they dry off and become these cute little fluff balls that wait in the nest for mammy or daddy to come home with a nice wee sprat or sand eel. They rapidly put on weight and have usually doubled in weight after just 2 days going from 10-12g to 24g!

Here is young Roseate chick at around 3 days old, at this stage they’re still little balls of cute fluff but have begun running around and searching for hiding places and shelter from the elements and predators.

The fluff ball stage lasts for about a week and then they begin transitioning to growing pins. This common tern chick is around 7 days old at this point has started growing their pins, the narrow tube like structures from which their very first set of feathers will emerge from. At this stage they have become quite mobile and start venturing all over the place away from their original nest site to any decent shelter or hiding place. Though venturing around the place comes with its own dangers as they can be pecked by other adults who are usually none too pleased to see these curious chicks that aren't theirs roaming around their nests and chicks.

This is a common chick that has reached a bit of an intermediate stage between chick and fledgling. As you can see it’s still quite fluffy overall particularly on its head and body but the wings are becoming quite feathery and chicks at this stage spend a good bit of time of flapping their wings about to start exercising their flight muscles and preparing for what’s to come. This chick is around 12 days old.

This stage I think is the point that I find them at their least cutest and is unofficially referred to as the great balding (by me) where their juvenile plumage has more or less fully emerged but not fully grown out on the head where the former fluffy top has fallen out and is being replaced by feathers.

Here is a fully fledged Roseate Tern, and this folks is what Rockabill is all about. If these young chicks can survive all the way through the trials and tribulations of early life where they must run the gauntlet of survival, persevering against food scarcity, exposure to wind, rain and being chilled to death and not to mention predation; they eventually take their place out on the rocks amongst the pantheon of great ones (i.e. the ones who survived) near the pools where there parents bathe, preen and sun themselves. At this point they’re capable of flying quite well but still not the best flyers just yet and many end up flying off and ending up in the surf to have to paddle back to the rocks and dry off before making anymore premature flight attempts. They’re also still reliant on their parents for food still quite some time, as the art of fishing remains a mystery to them for quite some time yet.

This fully fledged Roseate might be able to fly but it's still begging for dinner!

Well that's all folks, until next time. 

David Miley 

& The Rockabill Team