top of page

Pelagic Birds and Island Endemics of Madeira, Eastern Atlantic, June 2022

Updated: Jul 5, 2022

Zino's Petrel 16 June 2022 an endemic nesting bird of Madeira

Zino's Petrel 16 June 2022 - endemic. Nests in an extinct volcanic caldera high above eastern Madeira Island

SUMMER SCHEDULE: Bird Walks: 9:30am every Sunday, meeting at the Boathouse Restaurant/Cafe until 13 August when we resume 7:30am/9:30am walks. See here (click on that link!) for complete bird walk schedule. Ms. Sandra Critelli leads these July-early August Sunday walks: 917-495-2348 and

22 June to 22 July 2022

Birds of Madeira ("Isle of Wood")

In this Newsletter we send photos of some pelagic birds we share with a small volcanic island off the coast of northwest Africa, part of what is known as Macaronesia including the Azores, Canary, and Cape Verde Islands. To be fair these pelagic birds range up and down (and east to west across) the Atlantic - one large oceanic playground. We also send two forest endemics: Trocaz Pigeon and Madeiran Firecrest, plus Berthelot's Pipit that only occurs in dry grasslands here + the Canary Islands well to the south.

We traveled to this Portuguese island to see Fea's Petrel, that occasionally passes through Long Island waters, but we could get no good photos. However, the Zino's Petrel, is very very similar with a smaller beak - either species would be easy to recognize in our area by watching their buoyant flight style. See leading photo above and illustration below.

Several of the Madeira pelagic bird species are common in NY area waters in summer, particularly three species of shearwaters: Manx; Cory's; and the Great. A few of these shearwaters and petrels nest in the Madeiran archipelgo, and are sometimes easy to photograph, even from a heavily rocking boat. On the other hand, the Zino's and the Fea's, though endemic breeders, are rare even in these tropical waters. Best time of day to photograph is an hour or two before sunset as they return to their volcanic island nests on Madeira (Zino's) and Desertas (Fea's).

Northeast Coast of Madeira Is. in the eastern Atlantic - June 2022

Zino's Petrels forage offshore and return at night to their nests in a high elevation caldera (extinct volcano)

We did three 7-hour pelagic tours in mid-June 2022 with Wind Birds, an endemic Madeiran bird tour company (two employee-owners!). The package they offer consists of going to sea on three consecutive days from 3:00 pm until dusk (approx 9-10pm) - total coast $575 USD/person. There are two main areas we traveled to: north of Madeira Island (photo above), which seems to be the only place where Zino’s Petrel can be regularly found. The other is to the south of Madeira, which is better for storm petrels. Best days are windy ones, but expect 8-12 foot seas, and a return trip where you will get soaked (warm water), and bounced around a lot. Despite the tumultuous conditions (this is good because pelagic birds need wind!), we had a fine time: it was money well-spent.

Our HISTORICAL NOTES feature information on June seabird numbers off Long Island, and seabird die-offs in recent years in the western Atlantic especially two Shearwater species: the GREAT and CORY'S. What is killing them in large number? Is it bird flu, or certain weather conditions - and resulting lack of food?

Cory's Shearwater off Madeira Island in the eastern Atlantic - June 2022

Historical Note (a) was written in 1911 about Cory's Shearwaters and Great Shearwaters off of Long Island; Note (b) is a 18 June 2017 summary of the large number of seabirds seen from the shore of Long Island - why? In (c/d/e) are articles on seabird die-offs in June 2017 off Long Island (NY Times), with follow-up comments by two ornithologists that teach at the City University of NY; in (f) we present excepts from a scientific article explaining weather patterns that led to a mass die-off of seabirds in the Western North Atlantic near North Carolina; and finally (g) a June 2022 article that suggests that the bird flu (the H5N1 virus) may be responsible for killing large numbers of seabirds in the north Atlantic....

Manx Shearwater by Deborah Allen 16 June 2022 off of Madeira Island

Good! Bird Walks for early July to early August

All Walks @ $10/person - each in Central Park

For 10 July through and including 7 August: SUNDAYS only!

***Sunday, 10 July: 9:30am ONLY; Boathouse Restaurant/Cafe $10

Sunday, 17 July; 24 July; 31 July and 7 August = same schedule

The most current up to the minute schedule can be found HERE (click)

***Sandra Critelli leads the SUNDAY morning (only!) summer walks from 10 July through and including 7 August while we are in Africa (Kruger National Park) doing research on birds. Ms. Sandra Critelli: 917-495-2348 and Email:

Deborah and Bob will be back for the Fri/Sat/Sun/Mon August 12/13/14/15 Bird Walks. The most current up to the minute schedule can be found HERE (click)

Any questions send them our way: or call: 718-828-8262 (home)

Madeira Firecrest a Madeira Island moist forest endemic on 23 June 2022 by Deborah Allen

The fine print: *No need to book ahead or pay in advance - just show up at the right time and place and away you go with us! The summer walks always meet at the Boathouse Restaurant/Cafe...and after 4 July through early August, we meet ONLY on SUNDAYS at 9:30am. Please note: the Boathouse is not one of the buildings that surround the nearby Model Boat Pond - people make this mistake all the time! Summer walks are led by Ms. Sandra Critelli: 917-495-2348 and Email:

WEATHER: If in doubt about whether a walk will take place or not the morning of the walk: check the main landing page of this web site as well as the "Schedule" page - if the walk is cancelled, information will be posted there by 6am the day of the walk, and usually by 11pm the night before. If still confused and as a last resort, call us at home (718-828-8262) - if no one answers it means we left for the bird walk. We end all our Central Park walks (except Fridays) at the Boathouse at about 12noon to 1pm; you can get a cup of coffee and a muffin there (around $6 total). Walks last about 3 hrs (less if hot or rainy), and you can leave at anytime - we won't be offended. If you need directions/help to your next destination, just ask someone on the walk - we are a helpful group. ONE LAST NOTE: Sandra Critelli leads all the summer walks between 10 July and 7 August, if there is concern about the weather, call or email Sandra: 917-495-2348 and Email:

Chaffinch on Madeira Island 21 June 2022 by Deborah Allen

Here is what we saw last week (brief highlights):

Saturday 18 June through Sunday 26 June 2022 (inclusive).

Sandra Critelli led the bird walks on Sat-Sunday 18-19 June (and again Saturday, 25 June). As we've moved into summer, and past the time of migration, we focus on summer breeders/residents. The big highlight for everyone is the first discovered nest of GREAT CRESTED FLYCATCHERS in the Ramble (photos click HERE) - very low so one can watch the adults coming and going with food for the young ones in the nest. Lots of dragonflies...and for moisture, lots of fruit (mulberries and the last of the shadbush fruits). Other highlights included the resident lone GREAT HORNED OWL being attacked by robins, blue-jays and the occasional red-tailed hawk. Life's tough for an owl in Central Park, so much so that this bird (here in the park since January 2022) has re-located to the north woods along the Loch. Finally, on 26 June (Sunday), Deborah and I were back, and we found not one but two warbler species: adult male BLACK-and-WHITE Warbler (photos click HERE) and a female NORTHERN PARULA. This is the latest SPRING migration date either have ever been seen in Central Park.

Deborah's List of Birds in Central Park for Sunday 26 June 2022: Click Here

Grey Wagtail on Madeira Island - 15 June 2022 by Deborah Allen

Cory's Shearwater off Madeira Island in the eastern Atlantic - June 2022


Cory's Shearwater in abundance off Long Island. On 2 October 1911, I shot two Shearwaters off the coast of East Hampton, Long Island. I took them to be Cory's Shearwater (Puffinus borealis), but to make sure I brought them to Mr. W. DeW. Miller, Assistant Curator of Ornithology at the American Museum of Natural History who confirmed my identification. There were any number of them, together with some Greater Shearwaters (Puffinus gravis). The difference between the two species was apparent at quite a distance, the commoner bird [Cory's] appearing darker.

Willaim Tod Helmuth, New York City.


Robert Moses SP Seawatching 6/18/2017

18 June 2017

Compiling observations for the day yields the following remarkable numbers for Robert Moses SP yesterday:

Great Shearwater 669

Cory's Shearwater 48

Manx Shearwater 8

Sooty Shearwater 9

Wilson's Storm-Petrel 6

Northern Gannet 5

Parasitic Jaeger 1

Black Scoter 4

To put the Great Shearwater total in perspective, my previous high count from land on Long Island over 21+ years was 45, on 23 June 2001, at Democrat Point. The general pattern is for Great to be vastly outnumbered by Sooties during good early season flights, then by Cory's on good days later. In fact, in my Long Island seawatching experience, the overall frequency and abundance of Great from land has generally been very similar to that of the perceived-as-rare Manx: one or a few single-digit counts per year, versus many more and larger counts of Sooty and Cory's.

We await more data from other areas, but it is already obvious that the numbers of Greats from the Jones Inlet area were far in excess of any counts there in recent memory, and it appears that numbers from further east on the island were unexpectedly low (usually they increase steadily eastward). The occurrence of exhausted birds (including the Brown Booby) suggests a prolonged storm far offshore during prior days that was positioned in such a way as to trap birds in the New York Bight (if weather-savvy folks could check on this, I'd appreciate it). Locally at least, the wind speeds were never in the range that would cause shearwaters any difficulties.

Shai Mitra in Bay Shore, L.I.

Great Shearwater off Madeira Island in the eastern Atlantic: 16 June 2022

A Mystery of Seabirds, Blown Off Course and Starving

Hundreds of shearwaters arrived dying and dead on shores around New York City. Scientists suspect weather patterns altered by climate change.

Joe Trezza

JULY 14, 2017 – New York Times

LIDO BEACH (Long Island), N.Y. -- Joe Okoniewski has seen this before, just not on this scale. Each year Mr. Okoniewski, a wildlife pathologist with the New York State Department of Conservation, performs necropsies on small numbers of seabird specimens that wash up dead along the coastal parts of the state. The birds are usually lone adults or juveniles that strayed too close to shore.

This summer Mr. Okoniewski has already examined more than 20 dead birds, while twice that many are awaiting necropsies. All are the same species of agile seabird called great shearwaters, and all washed up emaciated on Long Island beaches last month in a mass mortality event that scientists say is extraordinary for the region.

Now Mr. Okoniewski and others are hoping the unusually large number of carcasses can provide clues into the mysterious lives of these birds, which are considered good indicators of the health of the world’s oceans.

“The birds are extremely thin and anemic,” Mr. Okoniewski said. “The big mystery is: Why are they thin? On the surface it looks like you know what happened: They starved. But when you ask why, it becomes much more of a mystery.”

The vast expanses of the ocean remain some of the most vital and hard-to-study environments on the planet. As scientists work to comprehend the scope of climate change, they often look to seabirds to tell stories from the world’s most inaccessible waters. Pelagic birds, which refers to seabirds that spend the majority of their lives at sea and rarely venture to the shore, traverse various regions and climates, are affected by extreme weather patterns and feed on prey exposed to carbon emissions — all while staying relatively observable above the water’s surface.

Greater shearwaters, which are long-winged birds the size of small sea gulls, nest on some of the world’s most remote islands in the south Atlantic, more than 1,500 miles from land, before migrating to the waters off New England and Newfoundland.

“These birds really illustrate the connectivity of ecosystems around the world,” said Shai Mitra, a biologist at the College of Staten Island.

Their sometimes-perilous journey takes them past Long Island each June, but only after they have fueled up at feeding grounds in the Caribbean. Living off fat reserves, they glide up the Gulf Stream, rarely venturing in sight of land.

Great Shearwater Deborah Allen November 2021 Cape Town South Africa

“They are sort of an enigma for us to understand them because they are so rarely seen,” said Paul Sweet, an ornithologist at the American Museum of Natural History who is preparing specimens of the birds and freezing them so that they are available for study in the future.

Which is why it caused a stir within scientific circles in late June when an offshore weather system pushed an entire flock not just within sight of land, but also over the shores of Nickerson Beach in Nassau County. Birders flocked to Nickerson to get glimpses of hundreds of shearwaters unsuccessfully fighting wind and fog, like flapping flotsam.

“Many of the birds were over land. Many were flying right on the shoreline,” said Isaac Grant, a birder from Staten Island. “I’ve never seen anything like it. Eventually, I stopped looking and started rescuing birds.”

Hundreds of carcasses were found over the course of two weeks, from Montauk west to Brooklyn and as far south as Cape May, N.J.

Steve Walter, a photographer from Brooklyn, arrived at Nickerson Beach to find straggling shearwaters battling the surf. He picked one up to protect it from the waves, “babysitting” it before rehabilitators arrived.

“I never imagined myself holding a shearwater in my hands,” Mr. Walter said.

Nearly all of the dozens of birds recovered by rescuers eventually died, and the bodies were sent to the state Department of Conservation, the Museum of Natural History or Cornell University’s Lab of Ornithology.

Most of the victims were young birds, Mr. Okoniewski said. Though bits of plastic were found in some of their stomachs, starvation, not plastic ingestion, remains the overarching cause of death, he concluded.

In years past, shearwaters have been found beached in large numbers in other parts of the United States.

The winds that forced the birds over land in and around New York City last month were relatively benign, further deepening the mystery.

Why couldn’t the birds fight them? What threw them off course in the first place? How long had it been since they had eaten?

“For a phenomenon of this magnitude, you have to make quite a large front,” Mr. Sweet said. “Why they were in that area of sea that had no food? I don’t know if we will ever know that.”

The beachings could say more about the health of the birds’ feeding grounds in the Caribbean than about the quality of the waters closer to New York, said Michael Schrimpf, a doctoral candidate at Stony Brook University who is specializing in seabird ecology.

“When we have these large numbers washing ashore at one time, how much different from normal is that?” Mr. Schrimpf asked. “That’s hard to know if we don’t have a baseline of what normal is.”


Subject: A Mystery of Seabirds, Blown Off Course and Starving - The New York Times

16 July 2017

Shaibal Mitra PhD

I think it's fair to say that the multi-hundreds of Great Shearwaters observed from the Nassau County shoreline on 18 June were off course. The species is entirely absent from this area for years at a time (I'd never previously seen even one from shore in Nassau in over twenty years), and the sum total of records over all time is vastly lower the numbers seen in just a few hours. Thus, their extreme concentration in a small area where they are ordinarily completely absent requires explanation. The fact that they were starving explains why many birds died, but alone it doesn't account for why they were bunched up in the New York Bight, rather than dispersing over a broader area of nearby waters they typically inhabit. All else equal, in the absence of food, one would expect widely foraging pelagic birds either to spread out randomly, or possibly to orient directly for traditionally productive areas, such as Block Canyon, Georges Bank, etc. -- if they could. Food shortage alone doesn't account for the unprecedented densities inshore in the New York Bight, unless they were actively seeking food in this unusual area, with seems very unlikely. I think they were starving,tried to keep moving,and wound up following a path of least resistance that brought them to where we encountered them.

Shai Mitra in Bay Shore, Long Island


Subject: A Mystery of Seabirds, Blown Off Course and Starving - The New York Times

15 July 2017

Richard Veit PhD

i don't see any evidence of birds being "blown off course". Starving, yes, and this seems likely due to shortage or lack of food, perhaps related to changing climate. But wrecks of great shearwaters of roughly similar magnitude have been occurring episodically for years, perhaps moreso in Massachusetts than on long island

Great Shearwater Deborah Allen November 2021 Cape Town South Africa

Mass Die-offs of Greater Shearwaters in the Western North Atlantic: Effects of Weather Patterns on Mortality

David S. Lee

In June of 2007 thousands of dead and dying Greater Shearwaters, Puffinus gravis, were reported at sea in waters off the northern Bahamas; subsequently, significant numbers were found washed ashore along the Atlantic coast of the southeastern US that same season. Media reports suggested that scientists were alarmed and feared that these massive die-offs resulted from some unknown ecological disaster. These concerns were widely circulated over the Internet, and various research institutions encouraged people to salvage specimens so that they could be examined for contaminants and other factors that might explain the die-off. Many causes have been suggested, including mercury poisoning, bacterial infections, and H5N1 avian flu. Necropsies of the dead shearwaters revealed little more than that the birds were very emaciated.

Actually, spring migration die-offs of this species occur regularly and probably nearly annually. The magnitude of the die-offs, the degree of documentation, and the amount of media coverage are of course highly variable. Weather conditions, notably offshore winds, in this part of the western North Atlantic are not conducive to washing dead birds shoreward. The Labrador Current and long shore currents carry floating objects southward, while the Gulf Stream transports Outer Continental Shelf waters north and east. As a result, only a small portion of passive floating marine objects such as dead seabirds are actually beached; thus seabird mortality could go largely undetected.

Life History and Migration

Greater Shearwaters are trans-equatorial migrants breeding in the Southern Hemisphere and, in our summer, “wintering” in the western North Atlantic. Breeding: This species’ entire breeding range is restricted to two small islands of the Tristan de Cunha group, Gough Island and Kidney Island off the Falklands, but despite its limited breeding distribution the species is relatively abundant. The breeding population is estimated at be 5 million-plus breeding pairs, and it is generally believed that the total adult population exceeds 6 million pairs. Wintering: In the western North Atlantic these shearwaters occur over cool pelagic waters both as summer visitors (during the Southern Hemisphere’s winter) and as migrants. Most “winter” north of 45° N latitude. Small numbers also occur in the Gulf of Mexico from May through October. Migration: Nearly the entire global population passes through waters off the southeastern US in the spring and early summer, with a modest number of sub-adults remaining off of the southeastern coast during the summer through November (age based on North Carolina State Museum specimens and lack of observed flight feather molt in “wintering” shearwaters off North Carolina, pers. obs.). Off North Carolina they typically occur in waters from 180 to 300 meters in depth (Lee 1986, 1995). The bulk of southward fall migration appears to be more over the mid- to eastern Atlantic.

Great Shearwater Deborah Allen November 2021 Cape Town South Africa

Biology at Sea

Greater Shearwaters are found over open seas where they feed from the surface, by plunge diving, and by following fishing vessels to scavenge offal. Principal food items are fish and squid, and to some extent crustaceans. These shearwaters tend to concentrate along current edges, around floating mats of pelagic Sargassum, and over schools of foraging fishes. They often feed in mixed species flocks. Examination of the digestive tracks of 43 specimens collected off North Carolina revealed mostly fish (50% occurrence, including Clupeids, Myctophids, and one jack, Caranx hippos), and squid or remains of squid beaks. Many of the squid beaks that were in the birds’ crops, based on wear, probably represent long-term accumulations.

Die-offs and Mortality Factors

Mass die-offs of Greater Shearwaters are reported from waters of the southeastern US on a regular basis. While reporting is limited from outside of US waters, these events are known to occur as far south as the southern Caribbean (Surinam and Trinidad). There are no reports of die-offs from the Gulf of Mexico where the species occurs less commonly. These events are restricted to late spring and early summer and often represent hundreds to thousands of dead and dying birds. Die-off events can easily go unnoticed because, as noted above, the currents along the southeastern US are not conducive to washing ashore birds dying in offshore waters, and the magnitude of mortality is probably often underestimated because the individual birds are widely scattered over various barrier islands and throughout different states. On several occasions I have had North Carolina charter boat captains comment on large numbers of dead and dying shearwaters they have seen in the Gulf Stream. Despite the regularity of this seasonal mortality, it has not been widely reported in the scientific literature, and the events are more likely to be reported by local media. While the scientific community is aware of the issue, and dead birds have been examined in attempts to determine the cause of these mass mortalities, nothing conclusive has been found, and as a result nothing has been published regarding these die-offs.

Timing of die-off events in relation to migration: Greater Shearwater die-offs occur mostly in June, but dates of documented occurrence extend from 28 May through 4 August. There is an 1893 report of many found dead on a South Carolina beach from sometime in late August, but this was storm-related. The peak time for die-off reports is between the third week of June and the first week of July. Beached salvaged birds are likely to have been dead and drifting at sea for days, and perhaps longer.

At these times, Greater Shearwaters are recently departed from their breeding grounds. Adults depart northward from their breeding grounds in April and May, and their fledglings leave the nest and begin to migrate north between May and August. The peak occurrence of Greater Shearwaters in the Grand Banks area does not occur until the second week of August.

In comparison, the Cory’s Shearwater, P. diomedea, is a similar-sized seabird that occurs off the southeastern coast of the US more commonly and is more regularly encountered than the Greater Shearwater. It is present at the same season, and feeds on similar prey items. Some individuals tend to occur closer to shore than Greater Shearwaters, and they are considerably more abundant both as migrants and seasonal residents. This species, however, is a bird of the North Atlantic and its migration patterns are trans-Atlantic. Because of their abundance and other factors Cory’s Shearwaters should be encountered much more commonly in die-offs if the issues affecting the mortality were of local origin. However, they are seldom encountered as beach-cast birds and there have been no documented region-wide, or even local, die-offs of this species. I point this out, as it provides indirect evidence that the causes of regular die-offs of Greater Shearwaters need not be factors originating in the temperate or sub-tropical waters of the North Atlantic. Along similar lines, during die-off events other locally occurring seabirds are not affected, and non-storm-related mass die-offs in all reported cases have been specific to Greater Shearwaters.

It appears that all of the Greater Shearwaters salvaged from die-off events are non-breeding birds (fledgling year, immature, and sub-adult individuals). Collection of live healthy specimens in the Gulf Stream off North Carolina indicates that the majority of the individuals migrating through and “wintering” in waters off the southeastern US are likewise not adult birds. This finding is based on plumage, molt sequence, gonad size, and the presence of bursas. (The presence of bursas in petrels confirms birds of hatching to one-year-old birds, but some, while still immature, may be older.) While the plumage of adult and younger birds is similar in overall appearance, adults are distinguishable in having dark caps and white necks that appear to be more contrasting because the white neck collar is wider and more defined. While “wintering” in the North Atlantic, adult Greater Shearwaters undergo a rapid molt of flight feathers between July and August. Adults collected (n=2) and observed at sea off North Carolina were in early to mid-molt sequences of primary feathers between mid-June and early July. While many non-adult individuals exhibited some molt of body feathers, none of our series (April through December) of pre-breeding-age birds were in the process of molting flight feathers. Specimens collected at sea were nearly all non-breeding age individuals. The presence of a bursa indicates birds are not of breeding age. All die-off event specimens examined for the presence of bursas had them (n=20), and nearly all of the specimens collected at sea off North Carolina also had bursas (n=50 out of 52). While many of the die-off individuals, based on feather wear and body feather molt sequences, were not first-year birds, none were mature adults. At this time it is not clear what proportions of the different immature age groups are represented in the mortality events.

Great Shearwater Deborah Allen November 2021 Cape Town South Africa

Evidence for the Influence of the Doldrums on Mass Die-offs

The weights of the beached dead and dying Greater Shearwaters are consistent with birds that have died of starvation. The molt sequence and plumage of these birds suggest many are young-of-the-year individuals, and bursa-based age determination suggest all birds to be of hatching and second-season age classes. The timing of the die-offs indicates that birds have recently arrived from the Southern Hemisphere. All of these factors lead to the conclusion that the birds associated with the die-off events are migrants and that the mortality is linked to stress related to the northward migration. Watson (1970) first proposed that the cause of these events is the result of the difficulty of migrants crossing the Doldrums in certain years. For reasons unknown, Watson’s paper has continued to be overlooked by people concerned with the die-off events. Here I am simply supporting his earlier conclusions with additional information that has accumulated since the late 1960s.

The Doldrums, the same equatorial windless seas that stranded large sailing ships for weeks on end, are a barrier to the wind-dependent migration of Greater Shearwaters. A belt of low barometric pressure that often remains unaffected by both the northeast trade winds and the southeast trade winds of the Southern Hemisphere creates a virtual no-fly zone for some seabirds. The influence of the trade winds in equatorial regions can be seen in, or measured by, decreased salinity, seawater density, surface evaporation, and barometric pressure; and increased precipitation, and air and water temperature. Combinations of these factors can increase or decrease the extent of the area affected. In the western Atlantic the northern trade winds seldom extend south of northern South America. The trade winds of the Southern Hemisphere shift from south to north as the Northern Hemisphere spring changes into summer. At their peak the northern extent of these winds occasionally influences the Northern Hemisphere seas as far north as coastal Venezuela. However, they typically blow briskly only as far north as the equator (and mouth of the Amazon) from June to January, and during the remainder of the year this region is under a prevailing calm. The axis of the calm zone that separates the trade winds of the two hemispheres is actually a few degrees above the equator. In that the shift of the southern winds to the north does not begin until the northern migration of Greater Shearwaters is already underway, any variation in timing or magnitude could result in many of the birds being forced to cross the Doldrums while the calm zone is still wide.

Cory's Shearwater off Madeira Island in the eastern Atlantic - 16 June 2022

The problem of the seasonally enhanced low-latitude no-fly zone is made worse by a general lack of food resources for surface-foraging seabirds in this region. The warm surface waters of the tropics hold little oxygen. Accordingly, measurements of plankton in the upper 50 meters of the western Atlantic are at their lowest between latitude 10° N and 20° S. Combined with the loss of wind-driven wave action, this scarcity results in limited marine productivity and opportunity for these shearwaters to effectively feed when they are in this area. The westward-flowing Atlantic Equatorial and Brazilian Currents sharply turn, respectively, to the north and south in this same general area, thereby eliminating current edges and other opportunities for the formation of oceanic fronts along which the birds could feed. These windless conditions deplete energy reserves as the combination of limited food resources, extra energy demands needed for flight, and increased time needed to travel through the area take their toll on the shearwaters. The result is shearwaters in stressed and starved conditions when they reach the patchy resources of the temperate North Atlantic. While it is not unusual to have high mortality in hatching-year seabirds, the seasonal mass die-offs reported here suggest that for this species low recruitment rates are the result of timing of migration as it relates to equatorial weather patterns.

Zino's Petrel 16 June 2022 an endemic nesting bird of Madeira

A Gull Flaps Its Wings and a Deadly Virus Explodes

Jim Robbins

June 17, 2022 – New York Times


This year’s outbreak of the H5N1 virus has resulted in the deaths of nearly 400,000 wild birds worldwide. Scientists are studying the pathways of contagion among species.

A great black-backed gull migrating from Europe to Eastern Canada last winter may have been the first carrier to North America of the deadly strain of avian influenza that has killed tens of millions of domestic poultry and devastated wild bird populations.

The wide-scale outbreaks have provided researchers with a new opportunity to fine-tune their understanding of the disease by studying which wild bird species, behaviors and ecologies play key roles in transmission.

“Previous studies looking at bird flu made these large categorizations of wild and domestic birds,” said Dr. Nichola Hill, an assistant professor of biology at the University of Massachusetts Boston and lead author of a new paper on the topic.

But “wild birds are incredibly species-rich,” she said, adding that “each of them has a unique natural history and behavior.”

Knowing which migratory species carry the pathogen, for example, can help predict when and where it might arrive based on migration routes.

After the migrating gull came ashore, the highly pathogenic avian influenza, also known as the H5N1 virus, exploded across North America. More than 77 million poultry, most raised in crowded conditions that fueled the spread and evolution of the virus, have been culled in dozens of countries.

Bulwer's Petrel off Madeira Island in the eastern Atlantic: 17 June 2022

For some experts, the toll wrought by this H5N1 strain on wild birds — it has struck more than 100 species so far — has been alarming and unprecedented in its depth and breadth. Among wild birds, the spread can be very difficult to contain, posing a greater threat of spillover to other wildlife. And some wild bird species, like cranes and some seabirds, are particularly vulnerable, especially those with low reproductive rates and those already endangered.

The World Organization for Animal Health estimates that more than 383,000 wild bird deaths can be attributed to the virus since October 2021, although the count may be a vast underestimate because of how difficult it is to track sick and dead birds.

The pathogen has spread rapidly through various regions and species, at much higher rates than during the last outbreak in 2014-2015.

“It’s impacting a bigger host range and doesn’t dead-end in wild birds like it used to,” Dr. Hill said. “It is sustained in wild birds, and that is a frightening prospect. For many of us in this field, my God, what do we do when we get spillover into a wild animal for which there is no control?”

It has long been assumed that the primary hosts for avian flu are dabbling ducks, such as mallards, teals and shovelers, that feed on the surface and just below with their rumps in the air. They are critical to the spread because they have mild or no symptoms and they carry it far and wide. The new study, however, found that other birds, like geese, played an underestimated role because of their natural history.

“Geese are a little more tolerant of human-disturbed areas,” Dr. Hill said. “Imagine a commercial poultry operation or backyard operation where they spread grain around.” That attracts “geese and other scavenging birds, like gulls and crows and magpies, so there’s an interface between them,” she said.

The unique natural history of the black-backed gull, the largest gull in the world, for example, plays a role in transmission. “Gulls were really rare hosts for highly pathogenic forms of the virus,” Dr. Hill said. “When they did carry it, those rare occasions, they spread it really quickly. There is nothing like a gull for a really rapid dispersal of the virus and really long distances. They will catch a tail wind and cross the Atlantic in 24 hours.”

The study may help other researchers track not only the continued spread of this year’s pathogen, but the paths taken by other viruses that are harmful to wildlife.

“Knowing that gulls, geese and ducks may be moving this virus in different ways is a big contribution to understanding or eventually modeling with more accuracy how to expect a virus like this to spread,” said Jonathan Runstadler, professor and chair of the Department of Infectious Disease and Global Health at Tufts University’s Cummings School of Veterinary Medicine and a co-author of the paper.

The data “allows us to predict if there’s a virus emerging, when that bird might enter North America and what bird populations we might target for surveillance to detect it,” Dr. Runstadler said.

The highly pathogenic lineage of this year’s avian flu originated around 1996, found first in a domestic goose in China. It has been circulating around the world in wild and domestic birds ever since, evolving as it travels from host to host.

In 2005, after a decade of evolution, the strain caused a large outbreak in wild birds in wetlands in China.

The strain showed up in the United States for the first time in 2014, traveling in migrating birds from Eurasia across the Pacific to Alaska and farther east, causing outbreaks at U.S. poultry farms that resulted in the killing of 40 million turkeys and chickens.

After it reached the Midwest, however, mass cullings stopped it, eliminating the viral spread for both wild and domestic populations.

“We don’t have a vaccine,” Dr. Hill said. “All we have in our tool kit is the swapping out all of our poultry, which is awful, but to some degree it was successful.’’

But killing off infected poultry hasn’t worked this time around, in part because the virus has been able to find a home in so many wild birds, spawning the largest outbreak of avian influenza ever.

In some places, officials have been warning chicken producers and even people who keep backyard flocks to keep their birds indoors, while in other places, the threat seems to have passed.

Manx Shearwater off Madeira Island in the eastern Atlantic - 16 June 2022

“This virus is so good because it Ping-Pongs back and forth between wild and domestic,” Dr. Hill said. “There is no better way to amplify a virus than taking a wild reservoir and domesticating a close relative. That’s exactly what we’ve done with chickens and ducks. Highly pathogenic forms of the virus only happen when the virus goes into agricultural animals.”

On Quebec’s Magdalen Islands, wildlife officials recently discovered the carcasses of thousands of white gannets that had been wiped out by the flu.

There is no way to predict whether the flu outbreaks will dwindle or grow worse.

Some species, such as raptors, seabirds and shorebirds, are also at great risk of catching the virus because of their behaviors. Dozens of bald eagles are known to have died of the flu, largely because they prey on ducks and other birds that carry the pathogen.

Birds that gather in large numbers are also at risk. “There’s a lot of flocking birds — shorebirds, terns and seabirds — that form massive, massive groups and that could just be a field day for the virus,” said Dr. Hill.

The extent of the devastation to various species is difficult to assess, because surveillance is lacking. Better tracking along migration routes would help experts figure out ways to mitigate the spread of the virus.

Deaths of large numbers of shearwaters and other seabird species have been reported along the Atlantic coast in Massachusetts, Maine, New Hampshire and Connecticut. The avian flu is a suspect, although tests have not confirmed that.

“The geographic extent of detection, the number of species that we’re getting with detections, the amount of disease we’re seeing in wild birds, this is all unprecedented,” said Andy Ramey, a U.S. Geological Survey research wildlife geneticist in Alaska who studies avian influenza. “It’s unknown territory and hard to know what to expect.”

There is also concern that during this year’s breeding season for many species, parents could pass the disease to offspring in the nest, which have underdeveloped immune systems. Young wild birds are often exposed to low-pathogenic viruses, which are common and can serve almost as inoculations, helping strengthen their immune systems.

One endangered species being monitored is the roseate tern on Buzzards Bay off the coast of Massachusetts. Testing is just getting underway, and no sick birds have been found yet.

Bulwer's Petrel off Madeira Island in the eastern Atlantic: 17 June 2022

“It does appear to be a rough food year for the terns,” said Carolyn Mostello, a coastal bird biologist for the Massachusetts Division of Fisheries and Wildlife. “Nesting has been slow. Hopefully we don’t have a combination of poor food resources and avian flu; that could act together to really injure the populations.”

Experts say the avian flu poses a very low risk to people and so far has been detected in only two humans. However, as it persists and evolves, it could gain the ability to pose a serious threat of spillover into humans.

Dr. Hill said that a major handicap to better understanding the outbreak has been the lack of funding for efforts to track the spread. “Surveillance is really, really, really bad,” she said. “We are spending very little money and time getting ahead of this.”


Deborah Allen and Robert DeCandido PhD Follow us on Twitter: @DAllenNYC and/or @BirdingBobNYC

E.P. Bicknell's residence on Hewlett Long Island in 1915

Berthelot's Pipit 21 June 2022 on Madeira Island Deborah Allen

Trocaz Pigeon 23 June 2022 on Madeira Island Deborah Allen

The Lighthouse at Pargo June 2022 = westernmost tip of Madeira Island


bottom of page