Time-lapse & report from 2018 CahowCam season

Click above to view Time-lapse of 2018 CahowCam season

Charles Eldermire | Cornell Lab of Ornithology:

 "We've been excited to watch the Cahow Cam community's response over the last two years to watching this uber-rare subterranean seabird's breeding attempts. Hundreds of thousands of viewers have spent over 15 million minutes watching the young cahow transform into a sleek juvenile. Beyond just watching, they've also shared their observations on social media, recruited new viewers into the fold, and been ambassadors for raising awareness of the tenuous success of the cahow recovery effort. We're looking forward to learning more together in 2019!"

J-P Rouja | Nonsuch Expeditions Team Leader:

This is the 6th Season that under our ongoing Nonsuch Expeditions project we have been streaming LIVE from the underground nesting burrows in Translocation Colony "A" on Nonsuch Island in Bermuda. The K-12 and Cambridge curriculum that we are developing with Cornell will further extend our reach into classrooms in Bermuda and  around the world! To obtain resources, teachers should contact us or signup for our Newsletter selecting the educator options. 

Please see the 2018 report below from Jeremy Madeiros, Chief Terrestrial Conservation Officer:

2018 Sees Record-breaking Cahow Nesting Season

Bermuda’s National Bird, the endemic and critically endangered Bermuda petrel, or Cahow (Pterodroma cahow) has one of the most interesting stories to be found in conservation and species recovery work. After being thought extinct for over 300 years, a small number of breeding pairs were re-discovered nesting on several small, rocky islets off the east end of Bermuda in 1951. A Recovery program for the species began by the early 1960s, when there were only 18 breeding pairs, producing a combined total of only 7 or 8 chicks annually. Since then, intensive management work has enabled the cahow population to begin a slow, but accelerating recovery, with the number of breeding pairs increasing to 55 by 2000 and exceeding 100 by 2012.

There were early indications that the 2018 Cahow breeding season was going to be another record-breaking one, with both adult birds and chicks being consistently recorded at higher than average weights. The adults were evidently exploiting food sources, most likely far to the north of the Gulf Stream, using their exceptional flying ability. (Geolocator studies in 2009-2012 revealed that Cahows regularly carry out foraging trips of 1,800 to over 4,000 miles over 3 to 7 days – just to feed the chick once!)

This resulted in healthy adult birds and well-fed chicks, with almost no malnourished fledglings that needed to be taken into care and given supplemental feeding.

The level of new nest prospecting by young adult birds just reaching maturity was also exceptionally high, reflecting the increasing number of fledglings produced annually by the nesting population.


As a result, it looked like 2018 would exceed 2017’s record of 117 breeding pairs and 61 successfully fledged chicks, and by the end of January, a total of 124 breeding pairs had been confirmed as laying eggs. During January and February, Carla Marquardt volunteered to candle all accessible eggs during my routine band checks and weighing of incubating adult Cahows, when adults are briefly removed from burrows for identification and a check of body condition. Candling is a technique used to determine if an egg is fertile and to follow development of the embryo inside the eggshell, proving to be of such value that it will be incorporated into future management of the species.

The chicks hatched in late February and early March and then spent three months developing inside their underground burrows, being supplied by the adults with squid, fish and shrimp-like crustaceans. By the time the last chick flew out to sea on 28th June, it was confirmed that 71 chicks had successfully fledged, breaking last year’s record number by 10!

The two new nesting colonies on Nonsuch Island, established by translocating chicks from the original, smaller nesting islets during 2004-2008 and 2013-2017 now both have breeding Cahow populations, with a total of 18 breeding pairs. These produced a record number (for Nonsuch) of 13 fledged chicks, including “Sunny”, 2018’s “CahowCam” chick, the hatching, development and fledging of which was again live-streamed by infra-red video over J. P. Rouja’s “Nonsuch Expeditions” website and the Cornell Lab of Ornithology’s Bird Cams project, enabling viewers in over 100 countries to follow the story of “Sunny’.

In addition, 2018 saw the first two breeding pairs establish at the second, “B” translocation colony on Nonsuch. One of these pairs consisted of a male bird translocated as a chick to the “B” site in 2014, with the female being “Backson”, the first ‘cahow-Cam” chick which fledged from the “A” site in 2013. Five additional pairs also were prospecting nest burrows at both sites during the season, and hopefully will lay their first eggs as breeding pairs next year.

It appears that the Cahow has now reached a point in which its population recovery has accelerated over the last few years. This is due to the intensive management programme, which has been able to control or reduce most of the ongoing threats facing the species, coupled with the re-introduction of the Cahow to a larger, managed habitat on Nonsuch, with room for population growth without the annual threat of hurricane damage or destruction of the nest burrows.

It should be noted, however, that 124 pairs are still a tiny overall population, and the cahow remains one of the rarest seabirds on the planet. The long-term objective of the Recovery Program is increasing the Cahow population to a minimum of 1000 breeding pairs, which will be needed to de-list the species from “Critically Endangered” to “Threatened”. We still obviously have some way to go, but the future looks increasingly positive for this symbol of Bermuda’s Natural Heritage.

Jeremy Madeiros | Senior Terrestrial Conservation Officer | Dept. of Environment and Natural Resources | Bermuda Government

NB: This article is copyrighted, please contact us via the form above for permissions to quote from it along with supporting imagery etc.

Nonsuch Island - Class of 2018

Meet the Cahow Class of 2018 from Nonsuch Island Translocation Colony A

- Portraits by J-P Rouja for LookBermuda

To vote for your favorite visit our Facebook Page

Easter Cahow Colony Update

All in all, it looks like we are going to have a record-breaking Cahow nesting season; although I will not be absolutely certain for probably a couple of weeks, the total number of Cahow chicks this year looks like it is between 67 and 70 (compared to last year's record number of 61 fledged chicks). The Nonsuch Colony also has 13 pairs versus the prior record of 10 from 2017.

Many of the chicks are also developing a bit more quickly than usual, most likely due to the generally high winds and stormy conditions in the Western North Atlantic all through March.  This is enabling the adult birds to make more feeding visits than usual during the vital early chick provisioning period, by utilizing free wind energy to make faster trips to & from the feeding areas. This certainly has been the case with the CahowCam chick, which has been fed on 5 of the last 7 nights, rather than the 2 or 3 feeds per week that is more typical.

Jeremy Madeiros | Senior Conservation Officer (Terrestrial) | Dept. of Environment and Natural Resources | BERMUDA

First Two CahowCam Chicks Have Returned!

Both "Backson" from 2013 and "Lightning" from 2014 have returned after surviving the odds of their first few years alone at sea.

Even more incredibly Backson, now confirmed to be a female has laid her first egg with her mate in a nest that they have been prospecting in Translocation Colony B on Nonsuch Island.

Jeremey Madeiros | Returns of 2013 and 2014 “CahowCam” Cahow Chicks

The present 2017-2018 Cahow breeding season has already produced a number of surprises and developments in the Recovery Program for Bermuda’s critically endangered National Bird, the Cahow or Bermuda Petrel, one of the rarest seabirds on Earth.

Since 2013, the team has been video monitoring one of the deep Cahow nest burrows on the Nonsuch Island Nature Reserve, to help fulfill one of the primary objectives of the Cahow Recovery Program, that of public outreach and education.


In 2013 an infrared video "CahowCam" (developed by LookBermuda as part of the Nonsuch Expeditions) was installed for the first time in the R832 Cahow burrow at the “A” Cahow colony on Nonsuch Island. This chick hatched on the 13th of March, 2013, and developed normally over the next 3 months, reaching a peak weight of 393 grams on the 6th of June. It then rapidly developed its adult feathers and carried out 6 nights of pre-departure exercising activity, coming out of the nest burrow at night to exercise and strengthen its flight muscles and imprint on the nest colony site. During this period, it “slimmed down” to a normal departure weight of 293 grams, fledging out to sea on the night of 16th June, 2013. The chick was then not seen for several years, living out on the open ocean and learning how to find and catch food, avoid predators, and learn how to survive on one of the harshest environments on Earth; the North Atlantic Ocean.

Over 4 years later, on the 5th December, 2017, I was carrying out a check of nest burrows at the “B” nesting colony on Nonsuch Island. This second site has had Cahow chicks translocated to it since 2013, in an effort to establish a second nesting colony on the island, following the success of the first, “A” colony. Earlier, on October 30th, one of the nests at this second site was prospected for the first time, with a male Cahow found in it that had been translocated to this site in 2013.

On this day, I could see a Cahow in the burrow that had already begun building a grass nest, and when captured and brought out of the nest for examination, I could see that it was one of the birds that I had previously banded as a chick. The band number, E0500, also seemed oddly familiar, so I checked my records and confirmed that this bird was indeed Backson, our first CahowCam video star! It was very satisfying to see that Backson had not only survived its risky adolescent period at sea, as typically only about one-third of fledging Cahow chicks survive this period to return as adults, but that it had already paired up with another Cahow.

Normally, new pairs of Cahows do not produce eggs during their first year together, but on the 22nd January, 2018, I found Backson incubating a newly laid, fertile egg in this nest burrow. I was also able to confirm for the first time that Backson was indeed a female. As of this time, we are just waiting to see if this egg hatches, which would happen in the next two weeks or so.

As if all this was not exciting enough, on the 20th January, 2018, I had discovered another newly returned Cahow, prospecting inside a nest burrow on one of the original small nesting islets. Upon examination of its band number, this bird turned out to be the second CahowCam chick, which was named “Lightning” by Sophie Rouja in the 2014 nesting season. This bird, from the R831 nest on Nonsuch Island, hatched on March 2nd, 2014, reached a peak weight of 422 grams on May 6th, and fledged to sea on May 27th, 2014. (This bird’s name was prophetic, as the CahowCam was knocked out twice by lightning strikes on Nonsuch Island while the chick was developing, which has led to a fair weather naming policy). So far, this bird has not attracted a mate to its new nest site, but we will continue to monitor for new developments in this regard as the season progresses.

Jeremy Madeiros, Senior Terrestrial Conservation Officer, Dept. of Environment and Natural Resources

Critically Endangered Bermuda Skink visits CahowCam Burrow

A Bermuda Skink was recently filmed visiting the CahowCam burrow as we wait for the female to return to lay her egg. Historically, they have a long-standing, important relationship with the Cahows as they help keep the nests clean.

Jeremy Madeiros | " The management and protection of the small nesting islands where the endangered Cahow nests also has an added bonus, in that this also protects a number of other native and endemic plant and animal species. One of the most significant of these is the critically endangered Bermuda Skink, which used to be common across most of Bermuda, but is now found only on isolated offshore islands and in a few small, fragmented populations in coastal locations such as Spittal Pond. It is now one of the rarest lizard species on Earth, and is found on at least 4 of the small islands where the Cahow nests. 

For many years, I have observed Skinks in Cahow nest burrows on these islands, often when the Cahows themselves are in residence. They seem to tolerate each other's presence, and there is evidence that the both species benefit from the association, with the Skinks using the burrows for shelter, eating insects, spilled food, infertile eggs etc., keeping the burrows clean and disease-free for the Cahows. It was known that a small colony of Skinks lived in the Cahow colony on Nonsuch, with surveys indicating that this population may have increased in the last couple of years; this was the first time that we had been able to record a skink visiting the CahowCam nest."

Mark Outerbridge | MSc, PhD, Wildlife Ecologist, Government of Bermuda


·        The skink is Bermuda's only endemic, four-legged, terrestrial vertebrate (in other words they are the only living land animal with a backbone to have reached Bermuda before humans, and they exist nowhere else in the world) 

·        Skinks are descended from a species that once inhabited the eastern U.S.A. and subsequently dispersed over oceanic waters to Bermuda (Brandley et al., 2010)

·        Fossil evidence indicates that skinks were living on Bermuda more than 400,000 years ago but paleontological and geological evidence suggest they may have been present here for 1-2 million years (Olsen et al., 2006)

·        Skinks were historically described as being very common, frequenting the old walls and stone heaps in the cedar groves of Bermuda (Jones, 1859). Now, most of the fragmented populations are only found within the rocky coastal environment.


·        Adult skinks grow to 15-25 cm in length and weigh between 13-22 g. Hatchlings are 6 cm long, weigh about 1 g and have bright blue tails (which fades as they grow older).

·        Skinks are thought to live for 20+ years

·        Skinks are diurnal and are most active mid-morning and late afternoon

·        Active year-round (they don’t brumate – reptile equivalent of hibernation - during the winter months)

·        Ground dwelling species (don’t climbing trees)

·        Omnivorous diet; insects, arthropods, prickly pear fruit and carrion from burrow-nesting birds (e.g. cahows and longtails)

·        Oviparous species (i.e. egg laying). Nesting occurs in May and June (3-6 eggs typically laid on the soil under rocks). Females guard their eggs.

·        Hatching begins in July and August after a 5 week incubation period.


·        Bermuda’s skinks are now on the brink of extinction. They are listed as critically endangered and receive protection under the Protected Species Act.

·        Habitat alteration and predation from introduced species are considered to be the main causes of population fragmentation and decline

·        The total island-wide (hence global) population was estimated to be 2300-3500 individuals (Edgar et al., 2010)

·        Skinks have been reported from at least 24 separate locations across Bermuda (Edgar et al., 2010) but the greatest concentration is found within the Castle Islands Nature Reserve

·        Various population assessments have been undertaken over the past two decades. Some of the fragmented populations consist of only 50 individuals while others number in the hundreds. The largest population is currently found on Southampton Island (estimated 500 skinks).

Nonsuch skinks

·        Surveys conducted on Nonsuch over the past 50 years suggest the population is declining and those skinks that remain are only found in a few locations on the island.

·        In the early 1960s, the vegetation on Nonsuch was mostly grass and coastal shrubs – ideal habitat for skinks (dense ground cover for concealment from predatory birds and rich in insect prey)

·        The reforestation efforts that have occurred since the 1960s drastically changed the interior of the island, making it less favorable as suitable skink habitat (Wingate, 1998)

·        The creation of the two cahow nesting sites is expected to benefit the skinks; as the cahow colony grows on Nonsuch, so too should the skink colony.