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A group of Conservation Travel writers visiting Bermuda with the Bermuda Tourism Authority joined Jeremy Madeiros and the Nonsuch Expeditions Team for a Tour of Nonsuch Island and met the latest chicks from Cahow Colony A.
Jeremy explains how the failure of the CahowCam 1 egg provides a much needed break for the parents that have raised a chick each of the past 5 years.
So far, the 2019 Cahow nesting season looks like it is a fairly successful one, with over 60 chicks now confirmed as having hatched, with the final number waiting for the current high winds and rain to abate so further nest checks can take place on the smaller nesting islets.
On Nonsuch Island, it looks like a total of 12 chicks have now hatched, including the first 2 chicks ever at the new, 2nd translocation colony site. With the CahowCam nests, the recently installed "CahowCam 2" camera recorded the successful hatching of its chick on the night of 9th March. This chick seems to be getting regular feeding visits by the parent birds and is gaining weight steadily.
However, at the "CahowCam1" nest, as the hatching window passed it became clear that the egg had failed and was not going to hatch. This pair has been unusually successful, raising chicks for 5 consecutive years in a row, whereas Cahow pairs are usually only successful every other year or at best 2 years out of 3. Usually, when an egg fails, the parents will faithfully continue to try and incubate it for at least another 2 or 3 weeks, which has been the case with this pair. Typically, once a pair finally accepts that an egg will not hatch, they often will kick the egg out of the nest or, alternatively, will partly or completely bury it with nest material. This is what has happened last night (20/21 March), when the adult brought large amount of additional nest material in, ultimately completely burying the egg. This is the first time we have observed this on the CahowCam, due to the pair being successful every previous year since the camera was installed! This points to the value of these burrow cams, that even when failure inevitably occurs, that we can still gain previously unknown insights and observations that were not possible before. The adults may continue to visit the failed nest on & off until around the beginning of April, then will depart for their mid-Atlantic summer habitat, where they will feed, regain their strength, and prepare for the start of the next breeding season in November.
All the best, Jeremy
Jeremy Madeiros Senior Conservation Officer (Terrestrial) Dept. of Environment and Natural Resource
On the final day of the Next Steps for Strengthening Stewardship of the Sargasso Sea workshop held at the Bermuda Institute of Ocean Sciences, thirty of the participants, including representatives from the Sargasso Sea Commission’s Signatories, Commissioners, and partners had the opportunity to take part in an excursion to Nonsuch Island with Nonsuch Expeditions. These participants had the rare opportunity to observe a scheduled nest check for two of the new Cahow chicks, as well as observe some of the species living in Sargassum.
At approximately 10:30pm on Saturday night, viewers from around the world watched as the Cahow egg in Burrow #832 began to hatch. Watch CahowCam LIVE Now
Nonsuch Expeditions Team Leader and CahowCam developer Jean-Pierre Rouja."The first hint that something was going on was a broken egg shell. Then, around 11:30pm, the chick’s head first appeared from under its parent. Progressively, throughout the night, more and more of it was revealed."
Senior Terrestrial Conservation Officer Jeremy Madeiros: “We were very happy to see the chick hatching in the 2ndCahowCam nest, and a bit surprised as I was not really expecting hatching to occur for several days yet. When I returned to my records, I could see the adult had returned during a stormy period in January when I had not been able to visit Nonsuch, so the egg was laid at the beginning of this period, not the end as thought. This brings the number of Cahow chicks so far confirmed as hatching on Nonsuch to 9, with adults in 4 nests still incubating eggs. The total number of chicks confirmed on all nesting islands now is over 45, with more nest checks scheduled over the next week, weather permitting.”
The CahowCam Project is now in its seventh season broadcasting LIVE from Nonsuch Island, and the third season in collaboration with the Cornell Lab of Ornithology (with whom over 15 million minutes of CahowCam video were watched over the past two years).
The new CahowCam 2 had just been installed in Burrow #832 only a few days prior to the hatching. It's one of several that the team is installing this season to give researchers, students, and viewers around the world fascinating insights into the nesting activities of the second rarest seabird on the planet. It is located alongside burrow #831 from which the current CahowCam continues to stream as it has for the past five years. Historically, Burrow #832 hosted the Camera for the first two CahowCam seasons (2013-2014) during which the same pair successfully reared chicks named “Backson” and “Lightning”.
The Minister of Home Affairs the Hon. Walter Roban: "I am so pleased to hear of another successful hatching at Nonsuch Island. I want to give a huge congratulations to the staff of the Department of Environment and Natural Resources who work tirelessly - sacrificing their weekends and evenings - to help bring our national bird back from the brink of extinction. Thank you also to Nonsuch Expeditions for enabling these incredible moments to be captured on camera and shared with a worldwide audience."
"Going forward we plan to be LIVE streaming both cameras in parallel to allow researchers and our followers to observe the similarities and differences in behaviors between the two pairs' nesting seasons," said J-P Rouja. “As we were going LIVE with this new camera during the most sensitive part of the nesting season (egg incubation), it was important to install the camera in the least disruptive way possible. Accordingly, we have custom-built new infrared lights to work with our new HD camera to fit in the pre-existing four-inch PVC pipe that remained in place from the original CahowCam setup in this same nest in 2013/14. This also brings us back to the traditional Top Down view that we used for first few CahowCam seasons, giving us an alternate wider view of the entire nest chamber from above. “
Jeremy Madeiros: “This Season we are working with international researchers to track the Cahow’s foraging expeditions using new nano-gps tags to shed light on where they are finding their food in the Sargasso Sea and beyond. In addition, there is concern that new proposals to carry out oil and gas exploration on the Continental Shelves may present a potential threat to the Cahow and many other seabirds, as previous geolocator tagging indicated that Cahows visit these areas regularly for foraging.… In parallel we are doing blood work to identify contaminants that may be exposed to through their food, all of which will assist with the ongoing management of the species.”
JP Rouja: “We archive each season in HD in its entirety, recording 24/7 for 7 months which we will combine with the maps generated by the Geo tags and the LIVE footage for the STEAM curriculum that we are developing with Cornell. This will be used Internationally in K-12 through University, and adapted locally for public and private schools where it is perfect for localizing and creating cross-curricular lessons that will better engage our students.”
Cornell Lab of Ornithology Bird Cams Project Leader Charles Eldermire: "I continue to be amazed at how close these rare petrels are to the technology and infrastructure that enables us to share their lives with the world. It's really a testimony to both the ongoing efforts of Jeremy and the Bermuda Government as well as the investment from Nonsuch Expeditions that our far-flung audience can now observe two sets of petrels."
David Freestone, Executive Secretary, Sargasso Sea Commission:“The Sargasso Sea Commission is convening a workshop this week in Bermuda and one of the issues being looked at is the connectivity between the Sargasso Sea, Bermuda and the wider Atlantic ocean system. The cahow, is an iconic creature that symbolizes the connectivity between Bermuda and the open ocean - particularly the Sargasso Sea and now this research will provide data to back this up. Its recovery is a great tribute to the dedicated conservation work of Bermudians which is being showcased to the world…”
John W. Fitzpatrick, Director, Cornell Lab of Ornithology: “The Cornell Lab of Ornithology is thrilled to partner with Nonsuch Expeditions in helping share with the world the intimate biology of these extraordinarily rare petrels, and the conservation success story they represent. We join hundreds of thousands of viewers in hoping that this new chick survives to fledging, and eventually returns to breed on Nonsuch Island.”
Meet the 2019 Nonsuch Island Cahow Chicks - Click for closeups -
CahowCam 2 on Nonsuch Island
A second CahowCam has been launched with a projected hatching window of the 10th - 17th of March.
Now in the 7th season broadcasting LIVE from Nonsuch Island, and the 3rd in collaboration with the Cornell Lab of Ornithology (with whom over 15 million minutes of CahowCam video were watched over the past 2 years) our Team has begun installing several new cameras this season giving researchers, students, and viewers around the world alternate views into the nesting activities of the second rarest seabird on the planet.
This new camera is located in burrow #832 right alongside burrow #831 from which the current CahowCam continues to stream as it has for the past 5 years. Historically, this “new” burrow #832 hosted the Cam for the first two CahowCam seasons (2013-2014) during which the same pair successfully reared chicks named “Backson” and “Lightning”. This season the #832 pair are once again incubating what looks to be a viable egg which is projected to hatch between the 10th and 17th of March.
Going forward we plan to be LIVE streaming both cameras in parallel allowing researchers and our followers to observe the similarities and differences in behaviors between the two pairs' nesting seasons.
Charles Eldermire | Cornell Lab of Ornithology Bird Cams Project Leader: "I continue to be amazed at how close these rare petrels are to the technology and infrastructure that enables us to share their lives with the world. It's really a testimony to both the ongoing efforts of Jeremy and the Bermuda government as well as the investment from JP at Nonsuch Expeditions that our far-flung audience gets to now observe two sets of petrels."
Jean-Pierre Rouja | Nonsuch Expeditions Team Leader and CahowCam developer: “As we are going LIVE with this new camera during the most sensitive, egg incubation part of the nesting Season it was important to install the camera in the least disruptive way possible. Accordingly we have custom built new infrared lights to work with our new HD camera to fit in the pre-existing 4 inch PVC pipe that remained in place from the original CahowCam setup in this same nest in 2013/14. This also brings us back to the traditional Top Down view that we used for first few CahowCam seasons, giving a wider view of the entire nest chamber from above.”
Watch both the original CahowCam and CahowCam2 LIVE here now.
As chicks start hatching throughout the Colony, keep watching the CahowCam and NEW CahowCam2 nests LIVE for the opportunity to witness an egg hatching
The egg in the original CahowCam nest is projected to hatch this week and then the egg in the New CahowCam 2 nest is projected to hatch in about 10 days…
Join Jeremy Madeiros as he inspects the nesting burrows in Nonsuch Island Translocation Colony A, and meets a few new chicks.
Save The Date: Monday February 11th, 7:30 pm at the BUEI
The Nonsuch Expeditions present a Cahow Season Update with Jeremy Madeiros and our collaborators from Portugal and the Cornell Lab of Ornithology Bird Cam Team.
Jeremy will give a summary of last years record-breaking season and updates from this one.
You will also learn about upcoming research using GPS based geo-tagging and upgrades to the award winning CahowCam system at the start of what looks to be another amazing season.
BUEI Members: $20 Non-members: $25 Students: $12
Tickets available by phone or visiting the BUEI gift shop | 441.209-0204 I www.BUEI.bm
5 pm: Sushi Happy Hour and À la Carte Menu at Harbourfront
7:30pm: Lecture starts, BUEI Auditorium
Ticket holders are entitled to 10% off dinner at the Harbourfront (food only) before or after the lecture. Please call 295-4207 for reservations and be sure to mention the lecture. Cannot be combined with any other special offer.
Backson the 2013 CahowCam chick has returned to Nonsuch Island and has laid an egg!
January 30th 2019 | Nonsuch Island Translocation Colony B:
Whilst conducting routine nest checks today “Backson” the Cahow chick from the first CahowCam Season in 2013 was found in Translocation Colony B on Nonsuch Island. Jeremy actually found her egg first, in a nest in the same burrow that she occupied last year, not being incubated, and then found her in an empty burrow a few feet away. It is not necessarily a problem for an egg to be left on its own for up to several days at a time and in this case she was more than likely taking a break from incubating exploring the neighborhood and wasn’t able to get back to her burrow by sunrise. She was put back in the correct burrow after her health check and will be checked on again later in the week.
She was named by Junior Explorer Sophie Rouja prior to fledging in 2013 based on a Winnie The Pooh story in which a note from Christopher Robin saying he would be "back soon" was misread as "Backson". This is what happens when a five year old picks the name :) yet ultimately proved appropriate as Backson was indeed back soon!
A multi-year collaboration has been launched with visiting researchers from MARE-ISPA and cE3c-FCUL (Portugal) who will work with the DENR and the Nonsuch Expeditions Teams to use GPS tags to track a cross-section of Cahows on their foraging journeys.
Jeremy Madeiros | Principal terrestrial Conservation Officer "The Cahow Recovery Program is committed to helping Bermuda's iconic National Bird recover from near-extinction and once again become an important part of the island's biodiversity. As such, we have always tried to utilize new management techniques and research technology in the program, so that potential threats to the Cahow can be anticipated, planned for and incorporated into ongoing management of the species.
Although we have managed to control threats to the Cahow on its nesting islands, establish new nesting colonies and greatly increase its breeding population, it is still critically endangered, and there is an incomplete understanding of its oceanic range and foraging areas. It is important that we understand where Cahows are finding their food at sea and whether, for example, areas where fishing pressure is concentrated or where offshore oil and gas exploration is planned may overlap with these foraging sites and possibly pose a threat to the birds.”
Geolocator Maps from 2009 study
Letizia Campioni | MARE-ISPA IU “Our project will enhance the ongoing Cahow Recovery Program by shedding light on their pelagic foraging behaviors and potential risks that they may encounter on the high-seas.”
Mónica C Silva | cE3c-FCUL “We are running a project with North East Atlantic Gadfly Petrels and we suspect that their foraging grounds may overlap exposing them to the same risks.”
The local Team has observed that over the past 2 seasons and continuing into this one, that foraging trips appear to be becoming shorter and more frequent. Cahows feed on cold water fish and squid traditionally found hundreds or even thousands of miles away in the North Atlantic basin, north of the Gulf Stream, but these shorter excursions raise the question as to where they may now be foraging, which this study will help answer.
Jeremy Madeiros | “Limited studies with geolocator tags in 2009-2010 made me realize that the Cahow can cover most of the North Atlantic Ocean in its yearly travels, but these had a large margin of error and were just a beginning for this study. I am excited about our collaboration with Letizia and Monica and the potential to focus in greater detail on important feeding areas for the Cahow and other aspects of its oceanic travels with these much more accurate GPS tags."
The longer-term geolocator tags register the time of day that the sun appears to rise and set and once this data is retrieved calculations are made to determine where in the world the subject would have had to be (within a 100 mile radius) for the sun to rise or set at the recorded time, giving their approximate location at sunrise and sunset each day for months on end.
GPS tag taped to tail feathers on Cahow
This season, the shorter-duration, but much more accurate GPS tags will be set to record the time required to contact the numerous GPS satellites at set intervals, which once retrieved can then be extrapolated to identify the GPS locations. In this way the tags do not need to process or calculate the actual GPS location in realtime which would require much larger batteries and processing power…
This allows the tags to weigh only 3 grams and when set to record at hourly intervals, the battery will last up to 2 weeks.
Jean-Pierre Rouja | The Nonsuch Expeditions “Not only will this data be useful to the Cahow Recovery effort, but we will integrate it into the STEAM Curriculum that we are developing with Cornell, giving students interactive real-world data to work with.”
The Portuguese Team is supported by a grant from The Mohamed bin Zayed Species Conservation Fund.
Watch LIVE as our Female Cahow has returned earlier than expected and pair will remain in the burrow for the day. Watch their interactions now.
The male had taken over incubation duties on the 14th and the female was expected to stay away for two to three weeks, so her return after only 7 days on the evening of the 21st was quite a surprise.
This is more than likely due to her finding a food source closer to Bermuda than expected as she usually needs to fly north of the gulf stream in the colder waters between Canada and the Azores to forage.
This also means that the male will still have plentiful fat reserves so won’t be ready to relinquish control of the egg just yet.
Cahows will not leave the burrow during daylight, so the situation gives our viewers an extended opportunity to watch the pair together.
At roughy 7 pm on January 13th, almost 3 days after his mate had laid their egg, the male Cahow returned right on schedule.
They then spent the next several hours together until she headed out to sea leaving him to incubate their egg for the next few weeks whilst she regains her strength.
Once she returns they will alternate shorter shifts incubating the egg until if all goes well, after roughly 53 days, it hatches.
Watch LIVE now: CahowCam
The 2019 CahowCam Nesting Season has officially started with the return of the female and the laying of her single egg in the early hours of January the 10th, exactly on schedule.
The incubation period is generally +/- 53 days, the first few weeks of which the male will take on whilst the female goes back out to sea to feed and regain her energy having just produced an egg almost a 1/3 of her body weight! Once she returns they will alternate shorter shifts on the egg until, if all goes well, it hatches in early March.
Jeremy Madeiros | Senior Terrestrial Conservation Officer (Bermuda Government)
I was happy to see the return of our CahowCam female last night just before midnight.
She flew in during the 35 to 40 knot gale just ahead of the cold front that came through, effectively using the winds as a fast lane to bring her back from her feeding grounds to the North.
Over the next 2 hours whilst I watched her preparing the nest and laying her egg, I could hear other Cahows calling in the background so it is clear that others came in with the same front.
As of 2 days ago 6 of the 18 nests in Translocation Colony A had returned birds and after a quick check this AM just ahead of the next cold front I can confirm that there are now birds in 9 of the 18 nests, 6 being females on eggs and 3 being males awaiting their mates return.
Over the next few weeks we will be incorporating “candling” into the nest check process that will allow us to track development of the chick embryos during the incubation period which usually lasts around 53 days.
J-P Rouja | Nonsuch Expeditions Team Leader and Conservation Tech Developer
“We had been watching for her return for the past few days and had alerted our Nonsuch Expeditions and Cornell followers to expect her over the next few nights, so it was amazing to see her show up exactly on schedule. As luck would have it her first activity was to rearrange the nest and in doing so she kicked some dried grass in front of the lens. Nonetheless out team and other late night viewers were able to watch her lay her single egg just after 1am, as Jeremy had predicted, within an hour of her return.”
Charles Eldermire | Bird Cams Project Leader Cornell Lab of Ornithology
“There's nothing quite like the happy, relieved surprise I felt watching the female Cahow amble into the nest burrow from the stormy darkness outside. I was also glad that despite her frenzied nest excavations, we were able to see her calm, determined focus as she laid a single egg. Everyone here is excited to see what the cahows teach us this season, and we're looking forward to sharing their journey with viewers across the world.”
Watch the ongoing nesting activity on our newly upgraded HD CahowCam LIVE stream or sign up for our Newsletter selecting the CahowCam alert option to be notified by email of significant nesting season milestones.
The countdown is on as we await the return of our female Cahow which in 2017 returned on the 10th and in 2018 on the 12th of January, laying her single egg within minutes of arrival.
Watch the newly upgraded HD CahowCam LIVE stream at www.nonsuchisland.com or sign up for our Newsletter selecting the CahowCam alert option to be notified by email as soon as our Team notices her return.
The male will usually arrive shortly after the egg is laid, taking on the first incubation shift of 2 to 3 weeks allowing her to go back out to sea and regain her strength. If all goes well, the entire incubation generally lasts around 60 days with the chick hatching in early March.
Our followers around the World spent over 15 million minutes watching our Cam over the past 2 nesting seasons and we have many new improvements and features in store for this year as we expand upon our partnership with the Cornell Lab of Ornithology.
John W. Fitzpatrick, Jeremy Maderios & J-P Rouja at the Nonsuch Expeditions CahowCam burrow.
As the Nonsuch Expeditions Team prepared to broadcast what is setting up to be another record breaking Cahow nesting season, John W. Fitzpatrick the Director of the Cornell Lab of Ornithology paid us a visit:
“After following the story of Bermuda’s iconic Cahow throughout my entire ornithological career, it was a real thrill finally to see Nonsuch Island firsthand and to meet its conservation and storytelling heroes. My regret, of course, is that we missed seeing the birds themselves by just a few days, but this only ensures Molly’s and my return during the breeding season. It is a privilege for the Cornell Lab of Ornithology to be streaming Nonsuch Expedition’s “CahowCam” to the world. I look forward to following along especially closely this year, now that I’ve personally looked down into that nest burrow! Best wishes for continued successes during the 2019 breeding season.”
Stay tuned this Season for the many new features that we are developing with Cornell and be sure to sign up to our Newsletter selecting the CahowCam alerts option to receive notices of significant events as they happen.
The upcoming 2019 Cahow Nesting Season is off to an early start with breeding pairs returning to their underground burrows on the Nonsuch Island Nature Reserve and its surrounding islets earlier than expected. Watch CahowCam LIVE Now.
Principal Terrestrial Conservation Officer at the Department of the Environment and Natural Resources (DENR) Jeremy Madeiros: "Many of the birds are returning a week ahead of normal, possibly due to favorable weather and good amounts of food in their traditional feeding grounds in the cold waters north of the Gulf Stream. The remaining breeding pairs should be returning by the first week in November and all the birds examined thus far are in good condition which bodes well for a promising breeding season.”
"Conditions this year seem similar to last year when the closer proximity of food led to more frequent feeding visits which contributed to the record number of chicks (71) fledging, breaking the old record by 10. We are looking forward to see how many new pairs lay an egg for the first time this season as we had record numbers of new prospecting pairs last season.
Last year’s record number of 124 breeding pairs will hopefully also increase due to the number of new pairs coming on-line, and may approach 130 pairs; this represents a significant recovery, thanks to an intensive management program, from the original number of just 17 to 18 pairs in the 1960s.”
Cornell Lab of Ornithology Bird Cams Project Leader, Charles Eldermire: "Viewers have been asking when the CahowCam would return, and we’re excited to share these intimate views of the Cahow pair during their November courtship. The new camera will allow us to see their breeding season progress in exquisite detail, capturing the complexity of the cahows' lives at a new scale. These recordings are hopefully the first of many, chronicling the continued recovery of these petrels thanks to the efforts of everyone involved in their conservation."
Nonsuch Expeditions Team Leader and CahowCam developer Jean-Pierre Rouja: “ Our star CahowCam pair were amongst the first to return with the female arriving on the night of October 25th and her mate on the 26th. The recently upgraded HD camera system was already streaming LIVE which allowed our followers from around the world to get a preview of the reunited pairs’ courtship activities, after having spending several months apart. They spent the first few days courting, preening, nest building and resting which will continue on and off for the next few weeks all of which can be viewed LIVE via the CahowCam page. If all goes well they will then spend December out at sea feeding and re-energizing before the female returns in early January to lay her single egg.”
"With the support of the DENR, this will be the seventh Season that the Nonsuch Expeditions CahowCam live-streams to the world. Over the past two seasons, through our new collaboration with the Cornell Lab of Ornithology, hundreds of thousands of viewers, including students from around the world, watched over 15 million minutes of CahowCam video!
As part of our ongoing efforts to leverage technology to assist with Conservation efforts we will be bringing several new features online this upcoming season which should extend our reach and increase public engagement even further. In parallel, we continue to develop our K-12 STEAM curriculum with Cornell which is also being pegged to the Cambridge system for Bermuda and International use. Educators should contact us via this website for more and sign up for our Newsletter."
The recent waves of Sargassum weed that have made their way to Bermuda have as usual contained a wide variety of fauna including juvenile pelagic fish.
Above and beyond the usual sargassum community the variety of species found depends upon the currents and time of year, and recently it has included juvenile Mahi-Mahi in the 1 inch to 4 inch range, several of which were collected by Species Collector Chris Flook.
Nonsuch Expeditions lead photographer Jean-Pierre Rouja documented these different stages some of which can be seen here.
Fortunately Bermuda has not thus far seen the destructive amounts of Sargassum that has flooded the Caribbean over the past few months, where it has been overwhelming various coastlines in some places so thick that turtles and dolphins have drowned, not being able to break through to the surface to breathe. The thick matts when amassed in a bay or coastline quickly start rotting and turn toxic killing all of the fish in the proximity as well.
At least for now, the Sargassum they are having problems with is not coming out of the Sargasso Sea, but instead from further South where it has been increasing in recent years. It remains to be seen if the conditions that have caused those increases will eventually affect Bermuda as well…
For more information please visit the Sargasso Sea Commission Website
Big thanks the BIOS for the pop-up studio space.
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:
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.
A Nudibranch with its eggs on Sargassum | photo by J-P Rouja collection by Chris Flook
A Sargassum Shrimp
Happy World Oceans Day from the Nonsuch Expeditions base in the Sargasso Sea!
Bermuda, as the only landmass in the Sargasso Sea, was historically and continues to be the perfect location from which to launch and host Expeditions. These include the original Beebe Dives, decades of scientific research and more recent filming with National Geographic and BBC Natural History.
This is the first of a series of Sargasso themed biodiversity portraits being produced by Nonsuch Expeditions Team Leader Jean-Pierre Rouja in partnership with the the Sargasso Sea Commission.
J-P was recently named as Honorary Ambassador to the Sargasso Sea Commission (along with Dr. Sylvia Earle, David Doubilet & other renowned Conservationists), for his ongoing efforts to document and protect the Sargasso Sea.
As part of its core mission the Nonsuch Expeditions continues to showcase and protect the biodiversity found in Bermuda, its surrounding waters and the Sargasso Sea.
These ongoing expedtions are being facilitated by a vessel provided by the SeaKeepers Society.
