Saturday, January 8, 2022

The Cahow Experience 2021 ~ by Kate Sutherland

As we move into 2022 we all can use some good news, especially on the conservation front and even more so on a seabird front!  The Bermuda Petrel (Pterodroma cahow), or Cahow as it is locally known, checks all of these boxes for us.  For those of you unfamiliar with this species, though if you're reading this blog you must have seen them mentioned before, the Cahow is what is called a Lazarus species.  A species that was once thought extinct, in this example for over 400 years, that is rediscovered.  In the case of the Cahow, it was just hanging on to existence when rediscovered in 1951 with seven burrows occupied.  Now seabirds are generally speaking long lived species, so it would not be impossible for them to go unnoticed for long periods of time especially when nesting in places humans do not frequent.  Dr. David Wingate was integral to the survival of this species, monitoring all nesting activity, creating new, artificial burrows to increase the population, removing rats from nesting islets, discovering that the White-tailed Tropicbird posed a threat to chicks and thwarting their entrance to burrows, taking the fight over DDT to the courts in the US, and taking Nonsuch Island in Castle Harbor back to its natural state.  In general, rescuing this species from the brink.  In 2000 current Chief Conservation Officer Jeremy Madeiros took over from David, having been his protege for many years, and began his own chapter in the story of the Cahow.  He carried on with David's work and added another layer - interacting with the birds by banding them, weighing and measuring them, and initiating a translocation program that took chicks from the smaller, low lying islets and moving them into a colony on Nonsuch Island which until this point had no nesting Cahows.  This program began in 2004 and presently there are two translocation colonies on Nonsuch Island which now hosts the second largest colony in Bermuda with over 30 nesting pairs!

In 2011 Dr. Robert Flood (Bob), organizer of the Cahow Experience, planned a trip to Bermuda to research the Cahow for his upcoming Pterodroma Petrel guide.  Keen seabirder Hadoram Shirihai joined him on this expedition as well.  That year they chartered a small dive boat to go to sea six times (photo below).  Bob was able to visit Nonsuch with Jeremy, yet left feeling like he needed more time at sea with these gadfly petrels.  He was able to organize another research trip the following year in 2012, again chartering a small dive boat and heading to sea eight times (photo below).  All but one of these trips registered only single digit Cahow sightings, and of those only a handful were even close!  Maximum seen on the 2012 trip was 10.  Again Bob was able to join Jeremy on Nonsuch for banding studies and see the nesting Cahows in the hand.  He had a number of people express interest in joining him to search for these rare seabirds in Bermuda so in 2013 he organized a small group.  That year the most seen on one trip was six Cahows.  I read about these trips on a seabird news group in 2014 and planned to join in 2015.  Having worked for Seabirding for almost 15 years by that time, I had seen a number of Bermuda Petrels, or Cahows, offshore from Hatteras, NC but the chance to see them where they nest was irresistible.  Not only did we see a number of Cahows at sea that year but we also had the first photographed Trindade Petrel for Bermuda on one of the trips!  Seeing these birds in the hand and learning about them first hand from David and Jeremy was life changing.  And to smell a Cahow?  Well, I was hooked!  Bob invited me to help him lead the tour in 2016 and the rest is history.  We had groups join us in 2017 and 2018 then we were unable to make it a go in 2019, and November 2020?  Well, you might suspect why that didn't run!!  So we were super excited to get back there this past November for another look at the Cahows and offer people the best opportunities in the world to photograph them and learn their story from the men who created it.

Our first inkling that this year would be different than all before came on Tuesday November 9, 2021 when, standing at Cooper's Point, we tallied FIFTY-ONE Cahows in view at once!  Yes, a jaw dropping number from our high count of 20 offshore in 2018.  Our first trip offshore aboard the R/V Endurance (photos below), the Bermuda Museum Aquarium and Zoo's vessel, found between 30 and 50 individuals!  During the 2020-2021 nesting season there were a total of 26 nesting pairs on Nonsuch, when we visited the island on November 12, 2021 Jeremy informed us that the 2021-2022 season has over 40 as I mentioned earlier!  As the population of this endangered petrel grows so does our knowledge about their natural behaviors.  When I first began visiting Bermuda six years ago the general idea was that the birds we saw offshore were younger, non-breeding individuals and that adults returned directly to their burrows.  I photographed some individuals that had dirt on their abdomens in 2018, this, Jeremy told me, was a result of burrowing or coming and going from a burrow.  So were these young birds just prospecting?  As it turns out, adults and younger birds make up the individuals we see courting and flying together offshore from Castle Harbor!  Jeremy now knows that these birds will be flying, calling, and courting near the translocation colony and then return to their burrows when he is on night watch.  When you ponder it, it makes sense that just a few birds who have never known life with hundreds or thousands of individuals might not exhibit the natural behavior expected from a large colony.

There were a number of firsts on this trip.  We had the highest counts of Cahow recorded since the 1600s and Jeremy Madeiros himself joined us for our final trip to sea (photo below)!  This final trip offshore gave us the closest looks yet at these gorgeous gadflies.  At least 50 Cahows were seen on November 16, some of which came right to the boat hovering close by before zipping away.  It was almost as if they could smell their keeper on the boat with us.  Those of you who are addicted to seabirds, more specifically tubenoses, like I am know that their sense of smell is unrivaled.  I like to imagine they could smell their strange looking companion who handles them at least once a year.  The creature who for some was their surrogate parent who fed them in the translocation colony.  How curious for them to smell, or hear him, at sea!  Regardless of the reason, the last trip was epic.  An adult White-tailed Tropicbird flew right over us as well to investigate, and while I hear that they are in the area during the fall and winter months, this was the first time these trips had recorded one that was not a rehabbed youngster being released.

Our final evening in Bermuda, November 18th, Bob was able to organize a night watch for myself and Peter Flood (no relation to Bob) with Jeremy.  Unfortunately the moon was just about full, but Jeremy thought perhaps if the cloud cover remained we might see a bird or two.  Another behavioral assumption shattered!  We had over six birds at once flying around us near the translocation colony there on Nonsuch Island just after dusk!!  They were courting and calling and we could clearly see them as they flew in the light of the full moon!  As we left that evening Jeremy said, "if we have a moment, humor me!  I'd like to check something out!"  We pulled up to Horn Rock (photo below), the islet with the largest nesting colony at over 40 pairs, and just as we neared a Cahow flew right by us!  Jeremy cut the engine and we sat observing the islet.  It was like a beehive of activity!!  Durning the full moon!  Who would have imagined?

Bob Flood and I will be heading to Bermuda again in 2022.  These trips are not traditional birding tours, but we offer the chance to take four trips offshore and to visit Nonsuch Island with Jeremy Madeiros to observe the Cahows in the hand as he checks nesting pairs to begin the season.  There is also the chance to go birding around Bermuda where a number of Nearctic species are possible.  In November 2021 our participants logged a number of wood warblers including Blue-winged, Black-throated Blue, Black and White, Tennessee, Blackpoll, Orange Crowned Warblers and more!  The endemic White-eyed Vireo can also be easily seen on land.  One of the locals in Bermuda, Lynn Thorne, organizes birding tours and will take people to some of the more productive locations for a donation towards her Wildlife Rehabilitation and Sanctuary.  If anyone is interested in joining us for this 2022 seabird adventure, contact Robert Flood - live2seabird@gmail.com - or myself (Kate Sutherland) - cahow1101@gmail.com

Thanks for reading!  Check out some images from Robert Flood's research trips and some of my photos from our 2021 Cahow Experience below ~Kate Sutherland, Seabirding, Hatteras, NC USA

Additional posts about the Cahow Experience can be found here:

Check out the Cahow Cam which has live footage from two of the burrows in one of the translocation colonies on Nonsuch Island!  http://www.nonsuchisland.com/live-cahow-cam  These cameras were the brainchild of Jean-Pierre Rouja, founder of Nonsuch Expeditions and the man behind the camera for Jeremy's updates.  Our group was lucky to have him with us on our visit to Nonsuch Island in 2021 (photo below).

First research trip in 2011 - pictured below Robert Flood (center), David Wingate (right), and Hadoram Shirahi (left)
Vessel used for the 2012 research trips - pictured below Robert Flood (left), David Wingate (center), Mike Danzenbaker (right)
The R/V Endurance owned and operated by the Bermuda Museum Aquarium and Zoo (BAMZ).  This is the vessel we currently use for the Cahow Experience at sea trips!
A handful of images from the 2021 tour taken at sea.  All taken by myself, Kate Sutherland.



And a few photos that I took while visiting the colony:



Horn Rock, the site of the largest nesting colony with 47 pairs this season (2021-2022)!!
Another view of the R/V Endurance as we headed to Nonsuch with Jeremy, Captain Nigel Pollard and First Mate Chris Burville.
2021 participant Graham Gerdeman taking video on our approach to Nonsuch Island
David Wingate (left) with Robert Flood (right), participant Nick Robinson is in the background.
Jeremy Madeiros (center) with Robert Flood (left) and Peter Flood (right)
Scanning for Cahows aboard the R/V Endurance with David Wingate
A panoramic photo taken by Jean-Pierre Rouja of our group on Nonsuch Island 12 November 2021.  Copyright J-P Rouja
And a still image taken from the surface cam also run by J-P Rouja in addition to the burrow cams from the full moon night watch 18 November 2021!

Tuesday, January 4, 2022

Friday December 31, 2021 - Searching for Skuas - Kate Sutherland

Our final trip of the year was scheduled for December 29 with a weather date of the 30th, but as the date approached, the weather foiled our plans and it looked like the only day that would be manageable was Friday December 31...so we checked with those who had signed up and most were willing to go during the small window of opportunity.  We even garnered a little more support from our loyal NC birders!  The water offshore of Hatteras is still pretty warm and even north of Cape Hatteras the temperatures are in the mid 50s.  It seems winter weather comes a bit later every year for us and the winter species with it.  But we've found some good birds out there in December in the past and Great Skuas are likely around somewhere...so always worth a look for our Big Year birders!  This trip however, was a bit slow on the bird front and the only pelagic species we turned up were a nice flock of Red Phalaropes, a totally unexpected Black-capped Petrel, and a Manx Shearwater.  The gulls and gannets were quite cooperative in the chum and we had all age classes of Northern Gannet plus six species of gull.  

After leaving Hatteras Inlet just after sunrise we decided to steam offshore, heading to Diamond Shoals Light Tower, then we headed north about 12 to 15 miles offshore of Hatteras Island - prime Great Skua territory!  There was a gorgeous blue / green color change just north of the light tower and this was where we found the Red Phalaropes. 
Hatteras local, Haley Rosell, brought a Northern Gannet with her that she had in rehab for a few days.  It had a sprained wing, but with medicine and rest she decided it was ready to go and wanted to get it out with us if possible.  She gave it the opportunity to return to life offshore on that same color change! 
It was so cool to see one of these birds up close - they seem to be made of porcelain with indescribable colors around the eyes and on the tops of the feet.  This also happened to be where fog settled in around us...  Unfortunately fog makes birding difficult at best and we had to deal with it for a couple of hours.  

Life in the water was bountiful and we encountered some playful, young Atlantic Spotted Dolphins, some hammerhead sharks, at least two large Loggerhead Turtles, and one very cooperative Ocean Sunfish (aka Mola mola)
all north of Diamond Shoals.  As we approached the shoals nearshore for our trek back to Hatteras Inlet, Jamie Adams spotted a distant Black-capped Petrel!!  Just 6 miles off the beach!  WOW!  You just never know what you'll see - what a nice new year's eve gift for us!  Back south of the shoals we found that one distant Manx Shearwater.  While our search for the Great Skua was unsuccessful (we covered all of the places we've seen them in the past), it was a nice day out there and we were able to eke out a list in spite of the unseasonably warm December weather!

Thanks to everyone who changed their plans around to still make it offshore with us even though we had to change the trip date, it was a great way to end the year and the season!  A huge thank you also to Ed Corey and Steve Backus for helping Brian and I lead the trip - we'll see you in 2022!
(All photos today are by Kate Sutherland)

Species List for December 31, 2021

Black-capped Petrel - 1
Manx Shearwater - 1
Red Phalarope - 25 to 30

Northern Shoveler - 4
American Wigeon - 2
Northern Pintail - 18
duck species - about 20
Surf Scoter - 3
Surf / Black Scoter - 20 +
Long-tailed Duck - 2
Bonaparte's Gull - 10
Laughing Gull - 27
Herring Gull - 154
Lesser Black-backed Gull - 9
Great Black-backed Gull - 17
Royal Tern - 2
Common Loon - 8
Northern Gannet - 64
Brown Pelican - 1

Bottlenose Dolphin - 23 to 25
Atlantic Spotted Dolphin - 4 to 6
Loggerhead Turtle - 2
Hammerhead Shark (scalloped or Carolina) - 5
Spinner Shark - 1
shark species - 1
Ocean Sunfish (Mola mola) - 1

Young Northern Gannet, this bird fledged earlier this year!
And a close up of the gorgeous facial features of a juvenile gannet
A third winter Northern Gannet in the fog...
A selection of Herring Gulls, second winter:
Gorgeous eye of an adult
A darker second winter individual
An adult with a Menhaden head!
One of the Lesser Black-backed Gulls that was following us as we approached the inlet in the afternoon

Sunday, October 31, 2021

Saturday October 23, 2021 - Final Fall Outing! ~ Kate Sutherland

Skies were overcast as we met at the Stormy Petrel II (late) Saturday morning.  Myrtle Warblers were eating bugs in the lights at the marina and we could hear them overhead.  Since the sun it so late to rise in the fall we didn't meet until 06:30, but by the time we made it to Hatteras Inlet, the sun was peeking out of the clouds and we headed offshore in choppy seas left from the wind the night before.  Winds were light from the north west and we found some shearwaters on the shelf in addition to cooperative Atlantic Spotted Dolphins!  The shearwater flock we encountered had both Cory's and Scopoli's (pictured below)
in attendance plus a few Great Shearwaters.  For many of our participants this was their first encounter with these species.  A Pomarine Jaeger also flew by on the shelf, passing closely by ahead of the boat it gave some nice views but there was no catching it!   
Just beyond the shelf break around 10:00 we found more shearwaters!  It was also here that we began to pick up some Wilson's Storm-Petrels.  We don't always see them at this time of year, so having over a dozen with us for most of our time offshore was spectacular!  They came close each time we circled back on the slick offshore and everyone had nice views of these small stormies from the Southern Ocean. 
It was awhile before we saw our first Black-capped Petrel of the day, but once we found them they were very obliging.  A short time later our first Pomarine Jaeger started following us in the slick, soon to be joined by another!  Both looked to be near adult or adult birds, one still had a long, though tattered, tail streamer. 
The Black-capped Petrels put on a nice show dogging these Poms and watching their incredible, acrobatic flight kept most of us in the stern content for hours (yes, the Poms were with us for over two hours!).  Audubon's Shearwaters were a bit difficult to see well, but nearshore at the end of the day we found one with a nice flock of Cory's, Scopoli's, and Greats that sat long enough for everyone to see it well!  There is a lot of variation in Audubon's Shearwaters, especially in the facial and underwing patterns.  Perhaps one day we will have more information about some of the different nesting populations of Audubon's in the Caribbean and we'll be able to tell more about the light form and dark form birds like we do for our Black-cappeds.  
Also of note offshore were the many Yellow-rumped (Myrtle) Warblers, a high flying flock of Great Blue Herons, and a young Lesser Black-backed Gull.  Thanks so much to everyone who joined us out there for our final trip of the fall, and a huge "Thank You" to all of our supporters this year!  Thank you also to Steve Backus for helping Brian and I lead this trip.  Our 2022 Schedule will be up later this fall!  ~Kate Sutherland (all photos today are mine)

Species List for October 23, 2021
Black-capped Petrel - 19 to 21
Cory's Shearwater - 7
Scopoli's Shearwater - 17
Cory's / Scopoli's Shearwater - 255
Great Shearwater - 20 to 21
Audubon's Shearwater - 5
Wilson's Storm-Petrel - 34
Pomarine Jaeger - 4
jaeger sp. - 2
Common Tern - 2
Lesser Black-backed Gull - 1
Great Blue Heron - 5
Yellow-rumped (Myrtle) Warbler - 21 to 22
Atlantic Spotted Dolphin - 12 to 15
Bottlenose Dolphin - 42 to 52
Monarch - 1

A few Black-capped Petrel images, always a crowd pleaser, and certainly one of my favorite seabirds!
Cory's Shearwater - nice ventral and dorsal view of one individual that we saw

Another Scopoli's ventral view:
And a Cory's type shearwater.  A number of birds we see have some white in p8, 9, and 10 but not 20% or more.  These could be Cory's?  Or poorly marked Scopoli's?  I just leave them as Cory's / Scopoli's!
Great Shearwaters were also cooperative!
An interesting view of a Wilson's Storm-Petrel
Our other Pomarine Jaeger
And finally a couple of the offshore Bottlenose Dolphins we saw!

Monday, October 4, 2021

October 2, 2021 - Fall Diversity - Kate Sutherland

Hurricane Sam was passing to the east of Bermuda over the weekend giving us just a bit of uncertainty about how much swell would reach us here in Hatteras and if it would cause any trouble for us getting across the bar and to the sea via Hatteras Inlet.  We were very happy to find things were quite nice for us to get out on Saturday with a long period easterly swell and north easterly winds setting us up for some good  conditions for seabirding!  Reports of shearwaters on the shelf had us searching the horizon as we headed offshore.  Around 0830 we found a nice flock of over a hundred shearwaters giving us the opportunity to show everyone Cory's, Scopoli's, Great,
and Audubon's Shearwaters sitting on the water and in flight!  The shelf came and went around 0930 and we started dripping some oil, but it took a little while for us to find our first Black-capped Petrels in the deeper water.  They seemed to be mostly sitting around early and we kept seeing small groups suddenly appear in the air around us.  Once we slowed and put more chum out, Wilson's Storm-Petrels found the slick and Black-capped Petrels started checking it out as well.  The Gulf Stream current was moving about 2-3 knots and with the wind against it, seas were a bit choppy in addition to the longer period swell from Hurricane Sam.  Sargassum, the brown algae with air bladders that is a typical feature of the Gulf Stream, was scattered around which meant Audubon's Shearwaters were out there and we had some nice views of these small black and whites offshore.  Just a handful of larger shearwaters were in the deep in contrast to the shelf waters, but that's okay because we had Black-capped Petrels out there! 
They were really showing off on Saturday and we had a number flying incredibly high before swooping down toward the sea.  Many times there would be two or three in a group arcing up into the sky before flying down one after another.  Our following group grew over the course of the morning and we had eight or nine back in the slick when I saw them chasing what looked to be a larger, pale bird way back behind us.  We circled back to get a better look and a pale Northern Fulmar came flying toward the boat!!  With a few Black-capped Petrels in tow.  
It was interesting to see the Black-cappeds exhibiting this behavior for a fulmar, because we typically see them harassing dark jaegers and skuas in this fashion.  A few petrels flying up behind the target bird and coming close, but not making contact, before veering away.  As many as six or seven Black-cappeds would work together to chase the fulmar, seeming to harass it and encourage it to leave the area. 
But, in true scrappy fulmar style, this bird was not deterred, and stayed with us feeding in the slick for almost an hour and a half!  Since we have seen larger birds like skuas feeding on dead Black-capped Petrels at sea in the past, we thought this behavior was akin to mobbing, a way to ward off a bird that is a threat to them.  But is it possible this behavior could be related to food?  A Black-capped Petrel exhibiting kleptoparasitism on Red-billed Tropicbirds was observed in the Cape Verde Islands recently (Peter Stronach personal comm).  It was pursuing these tropicbirds like a jaeger would until they dropped some food which the petrel would take.  The fulmar was larger than the Black-cappeds, so perhaps size could be a trigger for this behavior as opposed to coloration?  But we see them charge young Sooty Terns and Long-tailed Jaegers as well and Peter Flood photographed one pursuing an Audubon's Shearwater, all of which are slighter or smaller than a Black-cap.  We also regularly see them chasing one another around and Saturday we heard them calling as they fed on some chum together in a small group.  I imagine this behavior is more complicated than we know and we hope to compile all of our interactions into a note soon.
Once we got back to the shelf in the afternoon activity died down a bit so we picked up some speed to head back to the inlet.  As we were running along some of our participants saw what looked like a jaeger back at 0500, some distance from the boat.  Brian turned around to check it out and we found quite a nice little condition with some Sargassum and a number of birds!!  A young Long-tailed Jaeger was the bird that got our attention first and as we watched it it flew up into the sky in pursuit of something...
that was a young Sabine's Gull!!!  WOW!  The gull was obviously in distress as it tried to avoid the slightly larger jaeger on its tail, and it quickly disappeared into the sky presumably after giving up its last meal for the jaeger.  There were some cooperative Red-necked Phalaropes on this change and a number of Cory's type, Great, and Audubon's Shearwaters as well!  What a treat for the end of the day!  We have two more trips this fall, so hopefully this diversity will continue.
Thank you to everyone who joined us this weekend and thanks to Ed Corey for helping us to lead the trip!  Always a joy!  Photos in the post today are all mine - we might add some from Ed next week.

Species List for October 2, 2021
Northern Fulmar - 1
Black-capped Petrel - 58 to 71
Cory's Shearwater - 11
Scopoli's Shearwater - 11
Cory's / Scopoli's Shearwater - 216
Great Shearwater - 24
Audubon's Shearwater - 34
Wilson's Storm-Petrel - 60
Red-necked Phalarope - 7
Sabine's Gull - 1 immature
Long-tailed Jaeger - 1 immature
jaeger species - 1
Herring Gull - 3
Bottlenose Dolphin (Offshore population) - 11 to 12

Also seen on the shelf:
Lesser Black-backed Gull - 1
Laughing Gull - 24 to 26
Common Tern - 103
Atlantic Spotted Dolphin - 7

First, a few more images of the Black-capped Petrels and Northern Fulmar...
Black-capped Petrels were looking pretty sharp out there!
This one feeding on some chum looks to have a hole in the webbing of its foot!
We had a number of Cory's Shearwaters out there but most of my photos were distant.  Here is a nice view of what looks like perhaps a male Scopoli's.
There were a number of Cory's types that were not obliging in showing their underwings!  But we had a great time watching them feed in the Sargassum.  This one has an Audubon's Shearwater that just dove next to it!
Great Shearwater showing off the inside of its mouth and how they are able to keep ahold of those fishes and squid they like to eat!
An Audubon's flying near some Sargassum on the shelf in the afternoon.  Tough light, but you can see the long tail with dark under tail coverts.
Wilson's Storm-Petrels were super obliging during the offshore portion of the day showing off their long legs and even the yellow webbing on their feet!
One of the flyingfish that we encountered!  This individual doesn't seem to show dark pectoral fins like a blackwing flyer (Hirundichthys rondeletii), but otherwise looks quite similar to one.  Always interesting to see, photograph, and attempt to identify these awesome fishes!