Three years after installing new Leach’s Storm-petrel nest boxes we can happily report that three pairs of birds successfully hatched chicks!
A sample of three might not sound significant but this is a huge achievement for everyone involved with the nest box project. Throughout the season 15 boxes showed signs of use – whether that was a confirmed sighting of a petrel sitting in a box or indicators like a visible scrape, vegetation, a feather or the characteristic musty whiff that lingers for days once a petrel has visited. All these signs provide us with a sense of optimism that in years to come even more boxes might house breeding pairs – that really is something to look forward to!
We are interested in learning more about all aspects of this species’ breeding biology so the grand plan is to visit each chick every day until fledging to get weight and measurements. As Leach's storm-petrels incubate for 41 days followed by a lengthy developmental stage averaging 63 days in the nest, this is quite a time investment especially given our chicks asynchronous hatching; ‘Smudge’ hatched in mid-July, followed by ‘Squirt’ just over 3 weeks later and ‘Splodge’ 19 days after that. All-in-all, if all the chicks fledge (fingers firmly crossed!), I’ll have somewhere in the region of 100 consecutive visits to the other side of the island finishing up in late October. I really hope it doesn’t rain every day!
So, what do the chicks look like? Well, with six weeks between the first and last hatch date, they look completely different to one another:
Top - Bottom: Smudge, Squirt and Splodge - all photos taken on the 31st August 2017
At 49 days, Smudge weighed a whooping 81.2g – considerably more than ‘his’ parents who weigh an average of 45g - and ‘he’ still has 10 days of growing to do. This is not unusual, many petrel species pile on the grammes sometimes reaching 200% of adult weight before gradually losing mass before fledging.
Squirt had a few issues with the down on his tummy a week or so after hatching leaving a bare patch. But, that seems to have almost resolved itself.
And what of Splodge? He kept everyone guessing and hatched much later than anticipated. Parent petrels take turns to share incubation and can sit for several days at a time. Splodge’s delayed hatching does suggest the egg wasn’t incubated continuously and that, for one reason or another, the adult birds were unable to return to the nest to relieve each other of the incubation shift. This is known as ‘egg neglect’ or ‘intermittent incubation’ and petrels are one of a few species where the egg can withstand periods of cooling and still hatch, albeit slightly later than predicted! It will be interesting to follow Splodge’s progress and see how he develops over the next few weeks.
I cannot say often enough that this work would not be possible without the time, effort and dedication of a number of groups and individuals over the years. Thanks again to the Carpentry and Joinery students at Inverness College for constructing the first modified boxes, Steve MacDonald for designing and producing new and improved prototypes, and Richard Castro and the group from The Men’s Shed (Inverness) for taking Steve’s design and produce en masse - and in record time - the new set of boxes which are currently being occupied by birds today. All your contributions are very much appreciated!
Top: Students from Inverness College, Middle: Steve MacDonald (left) talking to volunteers at The Men's Shed, Bottom: 'Shedders' responsible for building the new nest boxes
I'll report back soon with updates on the trio's development....