With the recent discussion on the CT Birds Listserv regarding the upcoming Gull (plankton/barnacle larvae) feeding blitz that will occur in the western half of the Sound, I thought it would make a good report. This has turned out to be a very interesting and informative discussion, and for those who have never experienced this feeding bonanza in late february/early March, I have included some images from last spring. The images were taken in Bridgeport, Fairfied, Stratford and Madison. I posted the images throughout the text and below the discussion.
From Ron Ashford:
James O'Donnell, an oceanographer at thearticle about LIS water temperature. I believe he is submitting that to the Long Island Sound Study. The Millstone temperature record is too short to comment on trends for there are some long-term natural cycles that are influencing water temperature in addition to global warming. Jim has the temperature record from the former Noank Marine Lab (~1960's to ~1990) and recent discovered the
is preparing a summary Universityof Connecticut
NERACOOS is working to create climate graphs for all the northeast ocean observation sitesand its LIS partner LISICOS has create the first climate graph for dissolved oxygen http://lisicos.uconn.edu/clim.php . While the buoy data records are only ~10 years in length, these graphs show the average, the variance and also the current conditions. LISICOS is working on an interactive graph. NERACOOS hopes to roll out climate graphs by next summer.
Twan and I discussed this on Friday actually before the discussion on thelist in picking out a date. We're all thinking the same thing. See if you can come down for this evening and maybe peak-time gull event...Connecticut Audubon Society Conservation Technician Scott Kruitbosch will lead a public bird walk at Stratford Point on March 8 from 4 p.m. to sunset with an inclement weather date of March 9, same place and time. It will be a great chance to find some migrant waterfowl and new ducks for the season, a handful of newly arrived shorebirds and long-legged waders, and to see possibly thousands of gulls in the mouth of the
We will also discuss the conservation projects that Connecticut Audubon Society will be involvedwith in the coming spring and summer. The walk will be free and we suggest bringing binoculars and a spotting scope, if you have one. This is especially needed to help identify the many gulls we may be looking through. Make sure to dress for the season! It is usually safe to assume that this exposed coastal spot is windier and colder than much of the state. Please meet in the visitor parking lot by the buildings. Stratford Point is located at
Audubon Society Connecticut 2325 Burr St. Fairfield, CT 06824
CAS blog: ctaudubon.blogspot.com
CAS Twitter: twitter.com/CTAudubon
Email: skruitbosch at ctaudubon.org
2/29LI Sound before the rain/winter storm began. I discovered several hundred gulls sitting on the water, plankton-feeding, just off the Lordship Seawall at Marnick's Restaurant. Among them was an adult LESSER BLACK-BACKED GULL. I called a couple local birders. The wind blew the
, Lordship Seawall & Long Beach. I popped out briefly 10:30 to view Stratford
gull flock (& plankton?) west towardswhere I estimated 1000 gulls (60% Ring-billed, 40% Herring), including the LBBG and 1 Bonaparte's. By 11:30 the flock had dispersed somewhat, as well as was blown much farther offshore towards
. I was joined at Long Beach by Charlie Barnard, Long Beach
From Frank Mantlik, with Charlie Barnard
Stratford, - Adult LESSER BLACK-BACKED GULL, 1 Bonaparte's Gull Long Beach
with 1000 gulls (60%/40% Ringbilled: Herring) plankton-feeding. Also numbers of
Brant, Black Ducks, Common Goldeneyes, and Long-tailed Ducks.
Penfield Reef- part of the morning Gull roost at low tide-
Bonaparte's Gulls start arriving.......
.....and start surface-feeding.
Surface-feeding Ring-billed Gulls.
Two Lesser Black-backed Gulls on the reef that day.
From Bill Yule:
Re: the gull feeding behavior...
I have seen this behavior in the CT River in
Essexin both the Spring and the Fall.
I have posted about this before here but still the question seems unanswered "What are theyfeeding on?" Dennis says Barnacle larvae, Frank says plankton, someone else fish but how do we know these things? I'm curious has anyone ever dragged a plankton trawl through these gull flocks and ID-ed the food source or are the previous comments educated guesses?
Any references anyone could supply would be appreciated. Is it possible Blue Crab larvaeare involved? I ask because it seems to me Plankton blooms are something different from synchronomous larval hatches and it would be interesting to know if it's one or the other or both of these events.
I ran into Frank a couple of times last March atthis feeding activity (or frenzy would be a more accurate way to describe it) was happening. There were an estimated (conservative estimate) of 10,000 Gulls to a more realistic estimate
and the seawall when Long Beach
of 25,000 Gulls caught up in this feeding blitz. There were also high
numbers of Bonaparte's Gulls, Brant, Scaup and Black Ducks mixed with
the Gulls. He also located several
and Black-headed GLaucous, Iceland
Gulls. But it was obvious; whatever they were feeding on was floating
on or just below the surface of the water. I know Dennis, Larry Flynn
and Nick were out collecting the organisms that the Gulls were feeding
on (look at Dennis' earlier post).
This activity was also happening off
(with nearly 750 Short Beach
Bonaparte's Gulls one morning near the beach), Penfield Reef and
Fairweather Islandin . Like Frank I also found a Bridgeport
few other Gulls: 1 Glaucous, 2
, 2 Lesser Black-backed, 1 Iceland
Black-headed and a very possible Slaty-backed GUll all exhibiting the
same surface-feeding behavior.
However in early March last spring large flocks of Bonaparte's Gulls
were in close to shore at Hammonasset. The wind was strong east and
the birds were tucked in close to shore at the beginning of the
Moraine Trail near the large boulders and crashing waves. The birds
were feeding heavily on whatever was drifting just below the waters
surface. I photographed the birds that were very close to me. In
reviewing the images in my camera I could see the birds holding what
appeared to be small fleshy colored leech-like creatures about the
size of stretched soy bean. I walked near the edge where the waves
were crashing and these leech-like creatures were wiggling in the
water being pushed by the waves. I grabbed a few to look at and
realized I was looking at the fleshy creature inside slipper shells.
Not sure if this is a naturally occuring event in mating or the
creature has left or forced out of its shells. Maybe someone who knows
So it looks like these Gulls are feeding on a varied array of food items.
Keith Mueller Killingworth
From Hammonasset- Bonaparte's Gulls feeding on Slipper Shell flesh-
In answer to Bill Yule's questioning about the type of plankton upon which
the birds are feeding: the zooplankton (it swims) has been collected
numerous times from many locations and it is, almost without any doubt at
all, almost entirely barnacle plankton. I know that Dennis Varza and
Dr.Jack Barclay have pulled plankton nets behind Larry Flynn's boat (thank
you to all of them) from
east to about the Bridgeport/Stratford Norwalk
town lines. They were far enough offshore to be right in the feeding
lanes of the gulls and they identified the plankton as being composed of
barnacle larvae. I will leave it to Dennis, Larry and perhaps Dr.Barclay
to confirm the results.
I tried unsuccessfully to get the Bridgeport School of Aquaculture out
there to collect samples. The instructor with whom I met had no idea of
what was taking place. At least she was interested in finding out and
helping, but she and some of her class were about to leave for a fish
aquaculture meeting in
. I never got around to talking with her again China
after she returned. My fault on that one.
Anyway, I wound up collecting samples nearer inshore, from the end of
jettys where gulls were feeding and sometimes right along the shoreline
itself. I took the living zooplankton to Twan Leenders at the CT.Audubon
location at Stratford Point and Twan passed it on for analysis. There was
some disagreement as to what the plankton was in the samples which I took,
with some people (with a minimum of a Master's degree in marine sciences)
feeling that the plankton was mostly something called an ostracod. Others
never even looked at the samples to the best of my memory.
Here is a link to a good book on the subject. I think that you can read
through quite a few sections online. Click on the photo gallery section and
scroll down to the "copepods and lower crustaceans" subsection. Both
ostracod and barnacle cyprid larva are pictured. For what it is worth (and
it shouldn't be worth much) I agree with those who identified the larva as
barnacle larva. I studied the book photographs and looked at the samples
under a microscope myself, thanks to Twan having brought his own microscope
to Stratford Point.
"Zooplankton of the Atlantic and
: A Guide to Their Gulf Coasts
Identification and Ecology." It is by William S Johnson and Dennis M Allen.
Incidentally, quite a few years ago, a group of us saw feeding gulls in
multiple lines stretching from
Russian Beachin all the way to Stratford
the vicinity of Penfield Reef Lighthouse in
- as far as we could Fairfield
see with scopes set up. Each line contained thousands of gulls and we
estimated well over 50,000 birds. There were most likely more birds to the
west of our view, so 50,000 was probably a very low estimate.
Charlie Barnard Jr.
If anyone is interested, here's link to a photo of a sample I collected off of2009. We pulled a plankton net right through a flock of dip feeding gulls and brant. We measured about 2000+ specimens per cubic meter and they were all this animal, which we (non-experts) identified as the cyprid stage of barnacle. In addition to these, we had a very small number of segmented worm larvae.
in March Stamford
In response to recent e-mails
One can see this event anywhere from
Milfordto where one can Norwalk
get a good view.
Pt. Stratford Sea Wall Stratford Stratford Long Beach Bridgeport Seaside Park
Bridgeport St. Mary's
, Penfield Reef Fairfield Westport, Burying Hill Beach Sherwood Is. Westport St.Pk. Westport Compo Beach . Norwalk Calf Pasture Beach
Jerry Connolly reported seeing Gulls and Terns feeding off the
eastern sound of fish larvae.
That is a different phenomenon. It is later in the season and include
Terns and fish larvae.
The barnacles are usually done before the terns show up.
What to call the "Food"
Plankton refers to any small organism that floats in the water column
not swim through it.
Phyoplankton are the plankton that are green. When looking at buoy
data there is a reading of Chlorophyl -A and that gives an estimate
of the amount of Phytoplankton It generally goes up in the spring
with the increase in sunlight. and the increase in nutrients from the
The use of the word Bloom implies a refrence to Phytoplankton. This
may have an effect on the Barnacle Larvae.
Zoplankton are the animal part of the plankton. It can be anything
form fish larvae, crustacean larvae, worm larvae and assorted
Then there is micro plankton. Plankton nets have a certain mesh size
which determine what gets caught or not. At some point they found
that using a finer net got them a lot more organisms then they
thought was there.
Larvae are immature forms of organisms that are generally different
in morphology than the adults. ie. insect larvae, Frog larvae, Fish
larvae, Crustacean larvae. often time taxonomic identity is best done
by looking at the larvae. At one time Barnacles were considered
Could organisms other than barnacles be involves? Definitely, but it
would most likely be other places at other times. Blue Crabs? I can't
imagine crabs producing enough larvae to produce a drift of gulls
several miles long.
Over the past couple of years Larry Flynn John Barclay and myself
have been out on Larry's boat with nets and sampled the waters where
the gulls fed. Every time Barnacle Larvae. John has said that when he
was working on Greater Scaup, specimens would have their bellies full
of the larvae.
Barnacles go through several stages. the eggs hatch into a feeding
stage called the Nauplius After 6 months it transform into the Cyprid
stage. This is the stage being fed on. It look like tiny clams with
eyes and antenna, it does not feed and eventually attaches to a hard
surface. Towards the end of the event one will see the gull along the
rocky areas where the larvae settle out. The gulls will be scraping
the rocks with the side of their bills trying to get at them.
This is another case of Birders know one thing Marine Biologists Know
other things but little interaction takes place.
I find the current discussion fascinating anddecided to see what information is availableon the internet regarding SlipperShells which were mentioned in a post and are abundant along our coast. And, anyone who has been to
Here is just a snippet of info. More research into when they Embroys hatch in CT is needed!It may be possible that theGulls are feasting on Slipper Shell (Family Calyptraeidae) larvae that inturn are feeding on the plankton. Embryoshatch as pelagic larvae in some species or as crawling juveniles inothers. Field and laboratory evidence suggested thatthe postlarval juveniles crawled away from incubational substrates andassumed a drifting existence in the water column. The pelagic stage lasts for 15 16 days and that stage the shell and velum of the larvae grow.
Lots more sites too.
It could be a combination of several factors –hatching Slipper Shells eggs, increase in Plankton which the Slipper shelllarvae eat and perhaps Blue Crab (will research them latter.
Anyway, I find this topic fascinating and I hopethe experts will share the opinions as well.
Two of the many sites I visited
Lots more sites too.
Why didn’t I go to college for my first love…marine biology…..
Charlie Barnard suggested that we put up a couple of photos Twan Leenders took of thesamples Charlie provided him last year that he mentioned in detail earlier. Here they are in the CAS blog: http://ctaudubon.blogspot.com/2012/02/plankton-feeding-time-for-gulls.html
See for yourself and tell us what you think. Here's hoping we have many photos of masses ofgulls coming in the next few weeks.
Scott et al,I have a couple of marine biologist friends - one is a PhD who is a professor ofmarine biologyat a university. I can forward any photos to them and see if they can i.d. the samples.
Meredith Sampson Old
Gulls-flock mass feeding....A great discussion of the bird food chain from my point of view.Thanks for the responses to my questions and the discussion in general. Looking at the pics from CT Audubon they certainly look like barnacle larvae to my eye. I guess one of my follow-up questions is this one: Given a dense mass of plankton near the surface are there also fish feeding on this food source and if there are fish what are they and how do we know that the gulls are feeding on plankton and not fish? If I missed to answer to this question in the thread already posted my apologies but it seems to me that this is an interesting phenomena and a good one to discuss here. Someone mentioned duck stomachs filled with plankton and I understand this... but gulls seem to be a different category in terms of their food preferences?
Dennis - thank you for sharing the all that information! I find this event so interesting andwanting to know more so I've been reading what I can find about it. Unfortunately there doesn't seem to be a lot of information that pertains to Long Island Sound specifically regarding this subject or on CT's Slipper Shells.
To me there seems to be several events happening at this time. It is "spring" after all and flowersand wildlife a like are "blooming" around us everyday. Far from being even a novice in birding or marine biology, what I read leads to more questions and some observations. In addition to the Barnacles and other plankton that may be blooming now, I am inclined to think the Slipper Shells are also involved. There doesn't seem to be much info on the CT Slippers breeding cycle. But articles I've been reading say they spawn anywhere from March to August (or June to September) in coastal waters. They are found in large numbers in Europe (thanks to US Oyster exports),
I think this phenomenon as it pertains to Long Island Sound would be worthy of being studiedmore fully. How does it coincide with the migratory shore birds passing through or leaving our area? Did a milder winter cause an earlier spawn of all or some the different plankton? Etc., etc??
"The normal breeding period for C. fornicata in Woods Hole, MA is reported to be mid-Junethrough mid-August (Costello and Henley, 1973), however; it is likely that animals begin spawning in May, and a few animals continue to lay eggs in August. This seasonal limitation is removed by the fact that one can obtain animals from the wild between November and May that will readily spawn within days to a few weeks of being placed in warm (25 °C roughly 39 F) sea water. Animals can be kept in chilled sea water tanks at 12°C for up to a month, without feeding, and subsequently warmed to 25 C when embryos are needed. It is imperative that these “off-season” animals be collected from the cold and shipped with ice packs to prevent them from spawning during transport." http://www.life.illinois.edu/henry/crepidula_methods.html
Interesting article rehave used them to determine the age of Horseshoe crabs.
NantucketSlipper Shells. BTW - they are edible (see article). And, they
List of some articles I need to go through
Thanks for letting me share my "ramblings" on this subject. Please feel free to send myyour comments privately so we don't clog up the list here. Slipper Shells are quite interesting. And when out walking
From Paul Cianfaglione:
I really enjoyed the discussion about plankton feeding gulls. At first, I
had a hard time wrapping my mind around the idea of gulls with large bills
feeding on microscopic organisms. But after reading about Herring Gull
feeding habits, I guess it is certainly something to consider. Below is a
small excerpt from The Birds Of North America Online regarding Herring Gull
*At sea, forages in large, widely scattered groups that coalesce quickly
through rapid recruitment when prey concentrations located (**Hoffman et
*, **Pierotti 1988*<http://bna.birds.cornell.edu/bna/species/124/articles/species/124/biblio/bib099>
*). Often follows foraging humpback whales (Megaptera novaeangliae) or
groups of delphinids. Hovers over feeding groups grabbing fish, squid,
zooplankton concentrated at surface by mammals, diving birds, or large
predatory fishes swimming underneath concentration (**Pierotti
I understand that gulls may shift foraging patterns to take advantage of
short-term fluctuations in food supply. It just seems inefficient for gulls
to feed on microscopic plankton unless they are taking in massive amounts
at a time.
As an alternative thought, could gulls that attend plankton concentrations
be feeding on other prey items?? Many types of fry fish feed on plankton.
What may appear to be plankton feeding, could in fact be opportunistic fry
It's also worth noting that this is different from the feeding at Hammo described by Keith Mueller. He got some terrific pictures last year of the gulls with creatures in their bills that were easy to see. I don't personally know anything about the Slippershell ID, which Keith mentioned recently, but clearly those creatures were in that size range. This was different from the surface feeding in the western end of the Sound.
for the largest animal in the sea - the Whale. So if they can catch and subsist
on these small microscopic creatures etc, then why not Gulls? yes?
I remember seeing great thick blooms of microscopic Algae in fresh water, that
could easily be scooped up by any creature and eaten. By bird bills or any large
to small mouth. If food is there, than their is a creature that will take
advantage of it, no matter how big or small. Just my thoughts............
On July 31 of last year while fishing off of a rock pile mid-sound between
Feeding on them were many scattered gulls, including Greater Black-backed, Laughing and Herring; common and least terns; schools of filter-feeding menhaden (bunker); normally bottom-feeding fish including scup (porgy) and black sea bass; very small bluefish; and schools of small fish that looked like spearing. Feeding on the feeders were bluefish and striped bass.
In the few hours I was in the area the worms were steadily drifting by; certainly many hundreds of thousands and probably millions went within a few yards of my boat.
I have seen this hatch ( I believe they are spawning) many times around the
It is a remarkable event and draws the attention of the many opportunistic predatory birds and fish.
Again this event takes place in the warmer months not in the winter or spring. Years ago I did hear of something like this taking place close to shore on the south
Also of interest was the spawning cycle of the "slipper shells" as the water warms in early summer,
oysters are also doing the same thing at the same time, I'm sure these two species are not alone.
These images were taken at Long Beach in Stratford during the height of the feeding blitz! It was very difficult to photograph the birds so you could fully see the massive numbers of Gulls and waterfowl. The magnitude of the huge numbers of birds were not possible to capture on a few images. Just as Charlie Barnard stated above, the rafted birds stretched from Stratford Point all the way to Bridgeport. To understand how many birds were present, just imagine these images stretched out to the length of a few miles of shoreline! That's how many birds were there!
The day these images were taken, the wind was blowing strong out of the southwest so whatever mico-organism was present in the bio-mass, these birds were gorging themselves on what was being blown towards the shoreline. Because of the wind, the birds were speread out along the beach as far as you could see up and down the coast. Although with all of this activity going on, a large number of Ring-billed Gulls were heavily feeding on Slipper Shell flesh (just like the Bonaparte's Gull images above) along the eastern end of Long Beach by the point. I was standing very close to them and watched them gorge themselves on the snail-like flesh.
From Dennis Varza:
Some more on gull feeding
Many people have wondered about the efficiency of the gulls feeding on plankton. Here are some ideas.
When feeding the gulls sit on the water and the only energy involved is dipping the bill. I compare it to sitting on the couch eating sunflower seeds (I had a roommate that loved them). Compare that with Kinglets and Chickadees flitting about in winter feeding on scale insects. I am always amazed by the Chickadee that flies from the woods grabs a sunflower seed flies back to the woods open and eat the seeds and repeat.
If one wants to see the behavior at any time, go the Captains Cove Marina in Bridgeport. In the area of the Ice House with the fish painted on it is the outflow for the sewage treatment plant. There are always Ring-billed gulls feeding in there, sometimes Bonaparte's Gulls as well.
Concerning Slipper Shell Larvae.
Slipper Shells are Gastropods, they have a very different larvae (Trochophore) than Barnacle Cypris. (there are many other types of larvae) Also, the slipper shells generally reproduce later. One has to think of the different spawning seasons like the migration of different species.http://www.yesterdaysisland.com/2010/science/3-hermaph.php
The above web site covers a lot about Slipper Shells in the Nantucket/ Western Long Island area.
The species of barnacle here is Semibalanus balanoides
Back To gulls
If one pays attention to the three local gulls one would notice they are very different.
They have different roost site preference
They feed differently. Herring Gulls are bottom feeders when not looking for food in the rocky crevices of a bar or base of a bluff, they are out on the flats looking for clams. Ring-billeds on the other had are more top feeders looking for littile things on the surface. They frequent the flats at the water edge looking for little bits that get washed up. They naturally go for the little stuff. So it is natural that they usually make up the bulk of the drifts of gulls.
From Tina Green-
Flock of about 60 Bonaparte's Gulls just arrived on shore.
Stratford, foot of Cove Place (Russian Beach), 11:30 - 500 gulls scraping stuff off rocks as tide falling. Flock of 25 Bonaparte's flew by.
From Kathy Van Der Aue-
every bird seemed to have a golden glow about the head, so we gave up), Horned Grebes, Common Goldeneyes, a few Brant and Larry saw a Canvasback. We went to Compo and saw about seven Long-tailed Ducks, few gulls. At Burying Hill (in hopes of the absent Lesser Black-backed) there we also few
From Dennis Varza-
2:30 to 4:30 with Larry Flynn, Frank Mantlik, Dennis Varza
We started in the area south of Chimon Islands where Larry had the large numbers yesterday. The area was practically empty. We then worked our way to the east were birds were reported at Southport Beach and Sherwood Is. In the off shore area from Southport Beach To Penfield Reef Birds were everywhere. Looking in the water, we saw brown ribbons of clustered larvae. In some areas the larvae were below the surface and in such density as to turn the water brown. On the return trip closer to shore thousands more were found from Southport Beach to Cockenoe Island. The number of birds observed were so large that the estimates are very loose. We have come to believe that the gulls seen yesterday in Norwalk are the same ones in Fairfield today. And, likely the same ones in Stamford earlier in the week. It seems that they travel further than expected to find the barnacle plumes. Earlier in the week when Frank and myself had no gulls in the Bridgeport-Stratford area and they were not directly off shore, they were likely in the Norwalk-Stamford areas.
My gull numbers were largely in favor of Ring-billed Gull over Herring (at least 4:1). Some Bonaparte's Gulls were scattered between Oyster River and Charles Island with the largest group (40) being just east
of Charles Island. Amazingly, I did not come across a SINGLE uncommon gull species despite scouring a few thousand birds seen well enough to ID. Don't know what the odds of that are, but they can't be high!
Plankton-feeding waterfowl were also abundant, most notably Brant. Today I enjoyed watching a few species I had either rarely or never before seen feeding on the plankton, such as EURASIAN WIGEON, Lesser Scaup, and Bufflehead. This is an amazing event to observe, even if you don't hit the motherlode of gull numbers that Tina/Frank/Larry/Dennis had off the Westport area today.
On my way home in the afternoon I noticed that the plankton activity shifted further east, as I was scoping white specks on the water that were in the vicinity of Lighthouse Pt in New Haven.
Here are some locations and select numbers (not comprehensive), from
east to west.
West Haven, Bradley Point:
Ring-billed Gull 300
Herring Gull (American) 90
West Haven, St. John's By-the-Sea:
Brant 350 plankton feeding
Lesser Scaup 19 plankton feeding
Ring-billed Gull 200 plankton feeding
Herring Gull (American) 30 plankton feeding
gull sp. 450 plankton feeding
West Haven, Roberts St:
Brant 50 plankton feeding
EURASIAN WIGEON 1 drake among Americans plankton feeding
Ring-billed Gull 125 plankton feeding
Herring Gull (American) 75 plankton feeding
West Haven/Milford, Oyster River mouth:
Bonaparte's Gull 10 9 ad, 1 imm
Ring-billed Gull 1100
Herring Gull (American) 275
Milford, Beach Ave:
gull sp. 300 plankton feeding
Milford, Burwell Beach:
Bonaparte's Gull 16
Ring-billed Gull 70
Milford, Morningside Drive:
Bonaparte's Gull 2
Ring-billed Gull 24
Herring Gull (American) 2
Milford, Point Beach:
Bonaparte's Gull 25
gull sp. 650 plankton feeding
Milford, Silver Sands SP:
Green-winged Teal 2 plankton feeding
Bufflehead 9 plankton feeding
Northern Gannet 4 adults
Bonaparte's Gull 40
Ring-billed Gull 250
Herring Gull (American) 30
gull sp. 400
of coast. Highlights were 3 Lesser Black-backed Gulls and 300 Bonaparte's Gulls.
From Nick Bonomo:
3/18 - Westport, Sherwood Island SP - LESSER BLACK-BACKED GULL (first cycle), 5 Northern Gannets, American Pipit Westport, Burying Hill Beach - 2 LESSER BLACK-BACKED GULLS (adult and
3rd or 4th cycle)
(same 3rd or 4th cycle bird from Burying Hill Beach), 300 Bonaparte's
NOTE- With the unseasonable weather from the week of March 19 through March 23, Gull watching was impeded by morning fog on LIS.
From Frank Mantlik-
3/26 Southport Beach - just an update. The Bonaparte's Gull flock numbers 3300
birds, counted by tens to 1000 then extrapolated. The tide is now high and the
flock is resting on the water out of the wind off the private homes to the east
of Southport Beach.
The BLACK HEADED GULL (adult in full breeding plumage) flew in earlier, didn't
stay long, then departed (though probably still in area). Bob DeCandido and Deb
Allen also got to see it and photo it. I repeatedly looked through the flock but
saw no other rare species. At times there was much turnover of birds coming and
This is the largest flock of Bonies I've seen in CT in several years. I suspect
as the tide falls the flock may return to the mouth of Sasco Creek at Southport
Summary from Dennis Varza-
Part 1- People have a subjective sense of distance. What is far to one is close to another. In college, local students didn’t think much about driving 30 miles for a burger. Living in Fairfield, my mother wasn’t much concerned about going to Stratford for Shopping. But Norwalk, “Do we have to go all the way out there?” Near and far is as much about habit as actual distance.
When comparing sense of distance to birds, “As the crow flies” has as much perception as truth to it. Wings allow the coverage of distances in small amounts of time that we often underestimate. We see a bird in an area and expect it to be there, or the general area, all the time. The use of tracking devices has helped, but is still a problem for the average person. I read a paper about winter eagles in Maine and they found it was not unusual for some to spend the day on Long Island and still return to roost at night. We see a bunch of gulls on Long Beach in Stratford, we expect them to hang out there all the time, or maybe over to Seaside Park in Bridgeport. Is it really that hard for them to travel to New Haven Harbor, Norwalk Islands, or Port Jefferson for the day?
In trying to understand the interaction between the gulls and barnacle larvae we wanted as many observations of gulls as possible to see how the observed distribution is different than during a non-barnacle episode. We has observations as far west as Greenwich and as far east as Madison.
Plankton Feeding Gulls were seen in the area around Charles Island in Milford. Observers estimated numbers to be less than 5,000 and rather scattered. Further east smaller numbers were seen in West Haven near the Milford Border. In New Haven Harbor no concentrations were observed, In Guilford off Shell Beach a small group of less than 500 were seen, and none further east.
Last Year there were 10’s of thousands of gulls off the headlands of Stratford, Lordship to Black Rock Harbor in Bridgeport. This year birds were scarce in Lordship on Friday 16 Mar., but on the 17th numbers were low in the morning but increased in the afternoon to an estimated 3,000 birds.
From Chimon Island and west to Stamford, Shippan Pt. there were well over 10,000 birds on Friday 16th but were gone the next day.
The peak of activity was in the area between Penfield Reef in Fairfield and Cockenoe Island in Westport. Overall there were well over 30,000 birds present. Observers in the morning reported gulls close to shore in the morning and drifting further out in the afternoon. This indicates the plume of larvae were being pulled out with the tide.
The next day and increasing the the next several days, were record temperatures and a lot of morning fog and haze which inhibited further observations.
The barnacle event started on Friday in the Greenwich-Stamford then shifted the next day to the Westport-Fairfield area. East of there only small plumes were seen in Milford and Guilford. The Gulls observed appear to follow the plumes from great distances. So, on those days when the gulls “disappear” from the beaches and are not seen directly off shore were expected, are well likely to be miles away.
The distribution of the barnacle plumes are centered in the area from Stratford to Norwalk. Beyond this area they can be found in small numbers. As to when they occur is still problematical. For this event there was satellite data on Chlorophyl-a. On the 16th. There was no measurable Chlorophyl-a. while on the 18th, the western sound was dark with it!
There are many kinds of algae with many kinds of Chlorophyl. Chlorophyl-a is the bright green color found in most of the common algae. Because it is colorful it can be measured by the intensity of the color.
This past weekend, Drifts of gulls continued to be seen off Fairfield, but smaller numbers. I would guess that The gulls would have been of Stratford last week if they could be seen. Now, the final phase of the event should be seen. On jettys and rocky shore one will see the gulls scraping the rocks with the sides of their bills to get at the tasty tidbits.
Another thought on my mind is “How do Boanapartes Gulls fit into this?” Considering their small size one would expect them to really like barnacles. However, their migration in the state tends to be at the tail-end of the “season” so would only occasionally be experienced by them. When they do meet, they are rarely seen feeding! Is there something out there they like better?
Part 2- Background on the Barnacle Phenomenon
Earlier I mentioned that this phenomenon is unique to Connecticut, but never explicitly explained why. It is all because of Connecticut’s unique geography. Connecticut is separated from the ocean by Long Island and the Sound which were produced by the Glaciers. Long Island Sound is an estuary with properties very different from the ocean. I sometimes think of it as Chesapeake Bay on its side.
Barnacles need a rocky substrate and the distribution of rocky shores is very limited. Sand beaches go from Florida to New Jersey then along the south shore of Long Island, then up to Cape Cod. Hence no habitat for barnacles there. Rocky shores go from Mane south to northern Massachusetts then again from Rhode Island through Connecticut. Connecticut is kind of unique because the shore is a mixture of rocky headlands separated by rivers and streams and small sand beaches.
In the Harrison Ford Movie the “Patriot Games” there is an amusing mistake. Harrison Ford is an analyst working in the Pentagon (in Virginia). He has a birthday party at his house which is a mansion on a bluff overlooking the ocean. The nearest bluff overlooking the ocean would be Rhode Island. That would be a tough commute! In reality it looks like California.
Long Island Sound is funnel shaped, wide on the east ocean end and narrow on the west New York end. This condition forms several gradients. As one goes from east to west The differential in tide goes from 4 ft. to 8 ft. West winds blow water out of the sound making tides lower than expected. East winds blow water into the sound making tides higher than expected. That is why “Noreasters” are so devistating to the Sound. And, of course their effect diminishes as one goes west.
Sedimentary material from the rivers and erosion from the east creates the sandy beaches, such as they are. If one looks at the location of the sand beaches from east to west, they start out well up bays and coves such as Jordan Cove and become situated at the mouths of bays. Look at the bars of Milford Pt.
It is the sheltered aspect of the western Sound that promotes the formation of Barnacle plumes. Water has different properties for organisms of different sized. When one gets below a certain size water becomes more like molasses. As a consequence they have great difficulty moving in it. Large scale movements are determined by currents wave action. I recall a study in California where the amount of recruitment of barnacles at a particular location were determined by the direction of currents at the time of recruitment. If they were onshore they got great recruitment. If there were off shore currents they go little recruitment.
In western Long Island Sound. wave action is almost entirely determined by wind. The stronger the wind the bigger the waves. The direction of the wind also has an effect. The longer the reach (the distance the wind travels over the water) the greater the waves. When the wind is above 10 mph. one can expect 2-3 ft. waves increasing to white caps. When the wind is around 5 to 10 mph. one can expect 1 foot waves. Below 5 mph. the water becomes ripple to flat. It is during periods of light wind (less than 10 mph) that will cause the larvae to be stuck at the surface of the water. In the eastern sound one gets larger reaches and more waves in general.
So, although barnacles may be abundant and widespread from Connecticut to Maine, it is only the western sound that has the sheltered water that traps the larvae at the surface. In looking at a map the New England shore, Narragansett Bay caught my eye. Perhaps the bay provides enough shelter to produce the same phenomenon. I contacted Rhode Island Audubon and they reported nothing. The event may happen there, but on a scale too small to notice if one is not looking for it. I tried to contact Long Island birders and got no reply. I wonder if one has habitat like the south shore of Long Island to bird, does anyone bother to bird the north shore?