Click on the link above for the factsheet from BirdLife International’s
data base.
For more information on BirdLife International – go to www.birdlife.org
Rehabilitation of Abandoned Cahow
Conservation measures for the Eastern Bluebird
Reducing nesting starlings and sparrows to
help Bermuda’s Bluebird’s
Coffee and birds - the right brew for success
Longtail "igloo" nests for sale
Cahow
Encounters of a Special Kind
Rehabilitation of Abandoned Cahow
Jennifer Gray
Of all the visitors to the
A visit to Bermuda by Nicholas Carlile of the
NOTE: Those who saw
the illustrated lecture from Nicholas Carlisle while he was in
Conservation Measures for the Eastern Bluebird in
Andrew Dobson
The
Eastern Bluebird Sialia sialia is a
native species to Bermuda - the only location outside
- House sparrow Passer domesticus introduced in 1870-74 increased rapidly and began to displace bluebirds from natural cliff and tree cavities.
- In
the late 1940’s and 1950’s, a scale insect caused the elimination of over
90% of the cedar trees in
- European Starling Sternus vulgaris colonised in the 1950’s and increased competition for nesting cavity species.
- House Sparrows use bluebird nestboxes and are responsible for the slaughter of numerous bluebird chicks but starlings can be kept out by keeping an entrance hole size of 1.5 ins.
- The Great Kiskadee Pitangus sulphuratus was introduced in 1956 (to control the anolis lizard population) but proved to have a wide-ranging food preferences including taking young bluebirds from their nests.
- Pesticides
such as DDT were widely used in
- There has been a dramatic increase in the number of feral cats, especially since the introduction of cat feeding stations in the 1990’s.
- The tropical fowl mite Ornithonysus bursa has caused a significant number of deaths in bluebird nestlings.
- Vandalism by mindless individuals has resulted in broken nestboxes and dead bluebirds.
However, great efforts have been made to halt the decline in bluebird numbers:
· A nest box scheme has been in place for many years. The campaign was initiated by the Bermuda Audubon Society in the 1950’s.
- Workshops and publicity campaigns are regularly mounted.
- Efforts have been made to educate the public as to the plight of the bluebird and the part that individuals can play.
- Hundreds
of bluebird nestboxes have been erected around
- Bluebird boxes have been erected in ‘trails’ on most of the golf courses.
- A small number of sparrow traps have been used to remove sparrows from bluebird nest-sites.
The current population of bluebirds in
References:
DeSilva, S. (1992)
Swann, W (1982)
Wingate, D.B. (1968)
(This article was
submitted for the latest issue of the UKOTCF's Forum News)
How to reduce Starlings and
Sparrows - an attempt to help Bermuda's Bluebirds
David B. Wingate
Every
spring I get calls from people complaining of sparrows or starlings nesting
under the eaves of their houses. This poses a problem for three reasons:
i.
Noise in the roof and bird droppings on roof, window blinds and
porches.
ii. Infestations of maywings
which can invade the house.
iii. Accumulations of nest
material in the roof, which can pose a fire hazard.
There
is really only one practical way to deal with this problem -
EXCLUSION. This is done by stopping down the eave gaps so that these
species can no longer enter. It can be done with cement or by wedging or
nailing hardware cloth (square mesh wire) over the openings. The latter method
is best for retaining adequate roof ventilation. Starlings can prise open
loosely installed or delicate mesh so a sturdy job should be done. One benefit
of doing this in all houses that have a bird problem would be a reduction in
the number of these pest species. That in turn would benefit the Eastern
Bluebirds, which suffer severe nest site competition with these other two
cavity nesting species. Sparrows and starlings also nest in rot cavities in
trees, excluding bluebirds completely from such places. Starlings additionally
nest in cavities in cliffs and drystone walls, often very near ground level. In
the latter case the entrance holes are easily accessible so if you notice such
nest sites it would be a good idea to block them with smaller stones or plugs
as well, mercifully before the eggs hatch or after fledging. Starlings are
automatically excluded from standard bluebird boxes because they are too large
to enter the 1.5 in. diameter hole, but unfortunately this doesn't work with
sparrows because they are the same size as bluebirds. Nest site competition
with sparrows is, in fact, the major bluebird problem, resulting in the cruel pecking
death of MOST bluebird broods during the earlier part of the nesting season.
Fortunately most sparrows are finished nesting by early July, but failed
bluebirds will continue trying into August when they can finally be successful.
Dealing
with sparrow problems in bluebird boxes is a tough challenge. If you see a male
sparrow entering your box when you know there are bluebird chicks in it you
must act fast to save them. It comes down to a bitter choice. Either you catch
and kill the male sparrow or the bluebird chicks are going to be pecked to
death. We wish we could provide a fast and reliable 911 service for those who
report this problem but in practice there is seldom someone available who can
deal with the problem in time. There are two people in the Parks Dept. who are
licenced to shoot offending male House Sparrows with an airgun and if done in
time this usually buys the time for a bluebird brood to fledge. Trying to sneak
up and catch the offending sparrow when it goes in the box is another, but very
difficult option. Yet another is to quickly provide one or more nestboxes in
the immediate area hoping to divert the sparrows. But if you do this, and it
works, be sure to destroy the sparrow nest at regular intervals after the full
egg clutch is laid to keep them from breeding successfully! Reducing the number
of nesting places for starlings and sparrows in roofs and drystone walls won't
help the bluebird's immediate problem, and may even aggravate it in the short
run, but in the long run it should help by gradually reducing the pest bird
population.
Andrew Dobson
Imagine
Loss
of habitat and invasive species are seen as the main causes of decline and
threats to survival. In
What
is the real value of birds? As an economist, the question of economic value is
easy to explain but very difficult to quantify. In many societies, domesticated
birds provide food and many wild birds, if managed wisely, provide a
sustainable food source. In science, birds are one of the most studied groups
in the animal kingdom. New findings are constantly being made. Birds are
important distributors of seeds and pollinators of plants. They control plagues
and are excellent indicators of a healthy environment. The value of birds to
eco-tourism is immense. Some 78 million birdwatchers have travelled abroad on
birdwatching trips and it is estimated that they spend around $78 billion[1]
in the countries visited. Our own web site is receiving hundreds of ‘hits’ from
potential eco-tourists eager to find out what is to be found in
Birds
have a great role in folklore and mythology. Emphasis is placed on birds in
many religions and they are frequently seen as national symbols and emblems.
Birds appear in literature and the arts, featuring strongly in novels, poetry,
music and dance. Artists like Botticelli and Rubens have assigned important
roles to birds in their paintings.
To
many of us, it is the aesthetic value of birds that is so important. The sheer
pleasure and relaxation we get from seeing a Longtail fly along the coastline
or a Cardinal perched on top of the tree.
There are nearly 10,000 species of birds in the
world. BirdLife International has revealed that about 1,200 species have a real
risk of being extinct in the next 100 years. The main threats are habitat
destruction, introduced species and exploitation. It is not too late to act.
BirdLife has identified and monitors Important Bird Area (IBAs). Action plans
exist for threatened species and habitats. Biodiversity benefits from the
protection, management and restoration of sites. Groups in
Coffee and Birds – the Right
Brew for Success
Andrew Dobson
In
a recent edition of the Royal Society for the Protection of Birds magazine Birds, Winter 1999, members were given
the opportunity to reflect on their future consumption of wine – not the amount
consumed – but whether or not the bottle contained a real cork. The increasing
use of artificial cork is having a serious effect on the cork growing areas of
Now
it is the turn of the coffee drinkers to take note! The latest edition of Birding, Vol.32 No.1, the magazine of
the American Birding Association, highlights the advantage of shade-grown
coffee (coffee grown under a tree canopy). A few facts:
- Coffee originated in
- After petroleum, coffee
is second in terms of dollar value on world markets.
- 44% of
- Sun-grown coffee has
been genetically bred to be sun tolerant and high yielding.
- In 1990, 69% of
Columbian and 40% of Costa Rican coffee was grown in the sun.
- The monoculture of
sun-grown coffee results in a very poor avian diversity. This is supported
by much recent research.
- Sun-grown coffee
plantations require more chemical inputs – fertilizers, herbicides and
pesticides than shade-grown coffee.
- Plantations with
shade-grown coffee imitate many characteristics of a natural forest. They
provide much needed bird habitat and result in diverse bird life.
Although
sun-grown coffee may be higher yielding, there are numerous benefits recognised
in shade-grown coffee. Shade trees:
- Are frequently
nitrogen-fixing leguminous species.
- Prevent soil erosion
and seldom require replanting or attention.
- Discourage weed growth
and reduce farming costs.
- Provide wind
protection.
- Provide mulch from
fallen leaves.
- Protect hillsides from
being washed away in major hurricanes, as was the misfortune of exposed
coffee plantations in
Millions
of neo-tropical bird migrants pour through
www.songbirdcoffee.com www.sustainableharvest.com
www.si.edu/smbc/coffee.htm www.conservation.org
The New Batch of Longtail "Igloo" Nests - Ready
for Sale
In view of the success of the experimental artificial nests
for longtails developed under a Foreign & Commonwealth Office grant for
conservation in the
The igloo nests are being offered to private property owners who have coastal cliff sites suitable for longtails at $75.00 per nest. This price includes consultation advice on siting and installation, but does not cover the cost of installation. It is important to emphasise here that not all coastal sites may be suitable. These nests are designed for level cliff tops or cliff ledges (or level terraces with vertical retaining walls on the coast). In such situations they are easy and inexpensive to install, requiring only a mattock to dig a shallow depression, backfilled with sand for the nest, and about a bucket of cement to secure the dome over this depression and to camouflage it with a few natural slabs of limestone cemented onto the sides and top. The following diagrams illustrate the optimum installation scenario and design:
SKB coated styrofoam dome
Rock slab
Roof slab
Air
vent
Entrance
Level Cliff top
Vertical sides of
face of entrance Sand-filled
cliff nest depression
SIDE VIEW
Sand-filled
nest depression
Air
vent
Entrance
Slab
Rock
Cliff
Edge Level
cliff top
PLAN VIEW
Dr.Wingate fixing a
baffler to an artificial Cahow burrow.
Bermuda Petrel (Cahow) Conservation Programme
Since its rediscovery in 1951 after 350 years of presumed extinction, the Cahow has been assisted by an endangered species recovery program, initially supported by grants from the New York Zoological Society, and since 1966 as a program of the conservation division of Agriculture and Fisheries and now the Parks Department. This program has resulted in a slow, but accelerating increase in the population from a low of 18 nesting pairs in 1961 to 80 nesting pairs in 2007. The annual fledgling crop has likewise increased from a ten year running average of 7 fledglings per year in the 1960s to 24 fledglings per year in the 1990s and 39 in 2007. Indeed the Cahow Conservation Program is one of the most successful endangered species recovery programs on the planet at present, and its success is beginning to receive global recognition. Dr. David Wingate devoted his lifetime to the project. He retired as Government Conservation Officer in 2000. His successor, Jeremy Madeiros is now in charge of the recovery program and introduced the translocation programme.
The Cahow Conservation Program consists of five major activities:
1. Close monitoring of the breeding islets to protect against human disturbance or colonisation and predation by rats or other potential predators.
2. Protection of the nest sites against nest-site competition from the “longtail” or White-tailed Tropicbird, (which, at the time or rediscovery was preventing breeding success in two thirds of the cahow’s nesting sites). This is achieved by installing a reduced-sized entrance at each nest site which takes advantage of the size differences between the two seabirds and excludes the larger longtail from entering.
3. Provision of additional nest-sites in the form of artificially constructed burrows, which meet the cahows exacting requirement for a burrow so deep and / or curved that the light cannot reach the end of it. It is these artificial burrows, constructed where they are most needed and most likely to be colonised, that have enabled the nesting population to increase on the small islands where the relic populations survived.
4. Protection
and preparation of larger islands with adequate soil coverage for burrowing
such as
5. A
translocation project, which involves moving young birds to burrows on
The living museum project on Nonsuch began in 1962 with this limited goal but has since been broadened into a holistic restoration experiment for all of Bermudas pre settlement flora and fauna.
Cahow Encounters of a Special Kind
Jennifer Gray
It was not long before darkness fell and with eyes straining to focus in the shadows of the night I kept a constant sentry on the burrow opening where the anticipated emergence of a fledged cahow was surely to take place. At about eleven thirty-five the young cahow scooted out through the burrow entrance, quickly shook the dust from its plumage and proceeded to scramble uninterrupted up the rocky cliff face. The young cahow I watched that night stayed out for a very long time alternating between powerful uplifting wing exercises and poking and shuffling about in the underbrush. Long periods spent preening would be interrupted by a light sneezing of sorts as the bird cleared its airway. At around 2.40 am it was clear this bird was not going to fly tonight and I returned to the mainland in time to greet the next day.
That beautiful June night turned out to be the first of a series of Cahow encounters I was to have this season. It was followed by the arrival of an abandoned chick.
“Slick Pepper” as we named him arrived on of June 11th at a low weight of 171 grams. It was not known what had happened to the parents but it was clear that this cahow was not ready to fly and would surely die if not fed soon. Each night between 9.30 p.m. and 1.00 a.m. a special blend of shrimp, squid, fish and vitamins was meticulously blended and heated in a sterile environment and then fed to our dependent via a large syringe and feeding tube. For a time the food was welcomed and then it became apparent that a climb onto the top of my head for a wing stretch and flap was the preferred business of the night.
After eleven nights in captivity ‘Slick’ was looking good and had reached a weight of 347 grams. It was evident he wanted to take flight and had had enough of our fishy gruel offerings. Dr. David Wingate, my mentor throughout these Cahow experiences, carefully delivered ‘Slick’ back to the burrow in which he had hatched. Later that night we returned to the little outcrop of an island and experienced immense pleasure in watching the cahow emerge from the burrow, cling to a small projecting rock in a strong south wind, beat its wings with great purpose for a few short moments and then take off into the sky like a helicopter before veering over our heads and disappearing as a silhouette against the rising moon.
Only a day had passed and I was looking forward to returning to a less nocturnal habit when the call came in. “ I’d like to bring in another Cahow”, David said in a quiet and somewhat questioning tone. “I’ll prepare for it” I replied as I peered into the mirror and took another look at the large dark circles under my eyes. The cahows had an advantage over me - they slept soundly in the darkness of their artificial burrows all day as I went about my usual diurnal routines.
The second bird to come in was totally different in behaviour and size. Its bill was much smaller which David presumes to be characteristic of a female. This one also had a more prominent band of white across the top of the tail on an otherwise sooty gray background.
“Dainty Salt” weighed 168 grams on arrival at BAMZ and while she ate just as well she did not put on the weight as fast as ‘Slick Pepper’. She was a gem of a bird and immediately captured the hearts of all that had the opportunity to meet her. After seven days she had reached 287 grams and had lost interest in food. It was time for her departure. Like ‘Slick’, ‘Dainty’ was carefully transported back to the burrow she was raised in and we returned that night anticipating another exciting and successful departure of a cahow raised on our “Fledgling Super Fuel”. To our desperate disappointment we found ‘Dainty’ dead at the exit to her burrow - what had gone wrong? She appeared to be so healthy. It just happens that the day she was put back into the burrow was dead-calm and exceptionally hot and our inspection of the nest chamber following the chick death revealed an alarmingly high temperature. It seems probable that the bird was killed by heat stroke. It was now July and normally all cahows leave by the middle of June. However, we cannot rule out the possibility that the chick contracted a bacterial infection during the rehabilitation process and that this infection manifested itself suddenly after the bird was returned to the burrow.
A third cahow, which came in on ‘Dainty’s’ sixth night in captivity was only 134 grams and notably weak and dehydrated. An attempt to save the bird was unsuccessful and it was dead by the following morning.
At the end of these experiences I was physically exhausted and emotionally drained but on reflection I recognize that I have experienced one of the many marvels of nature. I learned so much about our indigenous cahows, both from working with David, a praiseworthy and very dedicated naturalist, and also from the birds themselves. The unfortunate death of ‘Dainty Salt’ in her burrow on that hot day in July may be a lesson for us that could lead to saving an entire colony of nesting cahows in the future. With global warming causing temperature and tidal extremes, we may need to put an action plan into place to cool, shade or otherwise protect the cahow burrows in the coming years. We will certainly need to keep a vigil on the temperatures within the nest sites to gain a better understanding of their normal temperature tolerances.
Jeremy Madeiros
Many species of raptors (birds of prey) stop over
on
The Barn Owl is a large bird measuring 14" in
length and having a 40" wingspan. It is mostly white underneath and a
beautiful tawny or cinnamon colour on top with grey markings. It has a characteristic
'heart-shaped' white face disc, which helps to focus faint sounds towards its
ears. Its night vision and hearing are about 100 times more sensitive than
man's.
Barn Owls were not found on pre-colonial
Jeremy Madeiros carried out research on the Barn
Owl in 1990. Throughout the summer, over 100 sightings of Barn Owls were either
personally observed or reported by members of the public. Through these
observations almost all active nest-sites were located and information gained
about the size of territories and the types of habitats favoured by the owls
for hunting. Some of the results of the survey are as follows:
i. Prey items have been
identified by analysing the regurgitated pellets of prey remains obtained at
nests and roost sites. There is a substantial variability of prey taken by Barn
Owls from different areas if
ii. They survey found 122
active nest-sites around
Tropicbird burrow in a quarry face. Another unusual
nest-site was in the ground beneath a Palmetto palm in Devonshire Marsh. Old,
unused nest-sites were located in a variety of locations ranging from church
steeples to limestone 'sinkhole' caves.
iii. In addition to
nesting pairs of Barn Owls, there is also a percentage of unpaired or singleton
adult birds. These usually comprise 25-30% of the adult population, which seems
to be confirmed by the number of sporadic sightings in areas of
Nest-sites should never be disturbed, as this may
cause abandonment. Some of the most favoured hunting areas in
The main threats to the Barn Owl on
The Barn Owl deserves protection as an important
predator of pest species on
The best place to watch for Barn Owls are in the
fields around the edge of Devonshire Marsh and along the edge of high coastal
cliffs such as Great Head Park, St. David's and Abbot's Cliff. First dark or
late dusk is the best time to see this most secretive and graceful of