Over two thirds of the Cahow pairs have returned and laid their eggs, including the record-breaking CahowCam1 pair which continues to challenge the norms…
At the start of this current nesting season, the male’s return on October 14th followed by her joining him on the 21st, (marking the official start of the nesting season), were the earliest individual-bird, and pair returns for nest building and mating logged by Jeremy in the history of the program. It historically used to start in November but over the past few years some of the pairs have been returning progressively earlier and earlier in October.
This pair have been nesting together in burrow #831 where the Nonsuch Expeditions custom built CahowCam1 is located since 2010, successfully raising and fledging a chick every other year, which is the average for the species, however similarities end there.
She is one of the largest females in the colonies, (and thus for the entire species), and one of the few matching or exceeding the weight of her mate. Just last week, as seen in the video below, she weighed in at 384 grams, (right after laying her oversized 61 gram egg), far exceeding the average female weight of 310-330 grams.
This difference may in turn be affecting their nesting behaviour. For most pairs, as documented by Jeremy over the past 20+ years, upon laying their single egg, that can be up to 1/5th of her body mass, the female will leave back out to sea as soon as her mate arrives to takeover incubation. This usually happens within hours, when they are properly synchronized, partly out of necessity as the female urgently needs to rebuild her fat reserves and strength, with the male generally taking on the first +/- 2 week incubation shift.
In the CahowCam1 burrow however, as revealed by the LiveStream once again this year, she usually does not leave right away and is reluctant to hand over incubation duties often staying on for the first week (as of this post on the 15th she is still there after 5 days, check the LiveStream here for a real-time view).
In their case, her refusal to relinquish inccubatioin duties results in arguments ranging from gentle nudging, to passive aggressive shoving, to full-on fights, which in some seasons have even contributed to the accidental failure of the egg.
This current season, the night before he was officially seen arriving, a mystery male arrived and spent 6 hours at times violently battling her to take over the egg, before giving up and departing. This was VERY distressing to watch for the Team and online followers as it seemed to be a nest invasion, and we feared for her safety, however, Jeremy now believes that it might in fact have been him, and she just wasn’t ready for his return, let alone for him to takeover incubation, and she pushed-back and resisted in ways that would have been impossible or even fatal for a smaller female…
Also, as seen in the video, and via the LiveStreams, there is a land-crab living in the burrow in the space behind the main chamber and camera (which is buried underground to give the side view of the chamber).
It has regularly been documented on camera when the Cahows are out at sea, stealing nest materials, likely to eat, pulling them into the back of the burrow where its own tunnels have been excavated.
During this last nest check J-P and Jeremy had intended to catch and safely relocate it away from the Colony, however as its’ own tunnels were too deep to reach it, it was decided for now to create a separate entrance to the crab tunnels that bypass the main Cahow burrow, with the aim to circumvent any potential conflicts…
Our viewers are asked to send us a note or DM should they see it in the burrow during the LiveStream.