May 15th update and CahowCam observations

The latest status of “Lightning” the Cahow chick and thoughts on what the "CahowCam" Burrow-cam has revealed: 

Nonsuch_May9_14 IMG_2241.jpg

As of Monday, 12th May, 2014, the Cahow (or Bermuda petrel Pterodroma cahow) chick named “Lightning”, in Nonsuch Island nest burrow R831, has reached the three-quarter-fledged stage of development and probably has only about two weeks to go before fledging and flying out to sea.

By 12th May, this chick had lost weight slightly as it had not received an adult feeding visit for three or so days, but still weighed 322 grams, or about the same as an adult Cahow. Its wing chord, or outer wing length, has increased to 207 mm (and will reach 265-275 mm by the time it is ready to fly out to sea). The soft grey natal down which completely covers the chick’s body when it is younger, has now fallen off and been replaced by the adult flight feathers on the chick’s face, wings, tail and shoulder area.

It is probably less than a week before the chick starts to emerge from the nest burrow at night to start exercising its flight muscles, explore the area around the nest, and imprint on the site, so that if it survives and returns as an adult in 3 to 5 years, it will return back to the same area and start looking for a nest burrow of its own to attract a mate to. If successful in this, the pair will generally return faithfully to the same burrow for the rest of its long life, thought to be at least 30 to 40 years in length.

CahowCam midseason observations:

The infrared “CahowCam” has enabled both the researchers managing the recovery of the Cahow, and the general public through live-streaming over a website, for the first time to look into the private life of one of the rarest seabirds on Earth, and follow the development of a chick in its deep, pitch-dark nest burrow. This has given us a new understanding of new aspects of behavior by the chick as it develops and the interaction between the chick and adult Cahows during the brief feeding visits by adults after long, multi-thousand mile foraging trips to gather squid, small fish and shrimp-like organisms for the hungry, growing chick.

Following are a few of the things that the “CahowCam” has revealed:

  • (1)  Cahow chicks from a young age seem to spend much time building up and re-arranging the nest material under themselves, showing that nest-building is an innate or instinctual behavior.
  • (2)  When not sleeping, Cahow chicks spend much of their time preening their down and feathers, especially around the growing wings. They also frequently spread, stretch and briefly exercise their wings in the nest chamber, especially as they get older. It was previously thought that their wingspan was too long for them to open their wings fully in the nest chamber, but as the wings lengthen, they often spread them out one wing at a time to fit in the restricted space of the burrow.
  • (3)  When the adult Cahows carry out a feeding visit to the chick, it usually lasts only an hour or two before the adult flies back out to sea. The chick is often so frantic and hungry when the adult first arrives that it swarms over and pecks at the adult bird. The adult has to preen the chick around its face and head for about 10 minutes, which seems to calm down the chick enough so that successful feeding can take place.
  • (4)  The chick inserts its bill crosswise into the bill of the parent bird, which regurgitates the food in a series of 16 to 25 very brief feeding periods, each lasting only 3 to 5 seconds, over a 10-minute period. Once the feeding is completed, the adult will then intensively preen the head and body of the chick, followed by a rest period where the adult sleeps next to the chick for up to an hour or more. The chick is often restless during this period, and the adult will often preen the chick for a brief period to calm it down before returning to sleep.
  • (5)  The adult after an hour or two will wake up, and sometimes completely pull apart the nest, throwing grass and leaves over the chick (which does not appear to be alarmed by this strange behavior). The adult may then feed the chick 1 or 2 more times before leaving the nest and flying back out to sea to begin another foraging trip. The chick then spends a couple of hours pulling the scattered nest material back together and rebuilding the nest. This behavior may represent “turning over the bedsheets”, aerating the nest material and preventing it from decomposing or building up insect or parasite loads. We are still scratching our heads a bit over this behavior.

The Infrared burrow-cam has already proved its worth, both in revealing previously unknown behavior and in allowing the public to follow the development of the chick at the same time it is seen by the researchers. It has revealed the private life of Bermuda’s critically endangered national bird to anyone, anywhere over the internet. We are looking forward already to the final stage of development of this Cahow chick and its departure out to sea, and are especially looking forward to November when the adults Cahows return to the burrow to start their courtship, mating and nest-building period at the start of another nesting season. We are sure that we will see many more previously unknown aspects of behavior at that time!

Jeremy Madeiros

Senior Terrestrial Conservation Officer

(Cahow Recovery Program manager)

Department of Conservation Services