Division of Ecological Perplexities Presents:
Red in Tooth and Claw!
HERONS AND LAND BIRDS
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All the land birds on Diego Garcia were introduced by man, or flew in from other islands. There are no 'native' land birds on Diego Garcia. There seems to be continuing straglers arriving every once in a while - in 1987-88, I noticed several "lost" birds on the island. On the way out to the plantation one day, I saw a hawk the size and coloration of an immature Redtail hawk, but with a shorter head and tail. It was in the company of a bunch of noddy terns and was flying through the trees beside one of the barachois. On another expedition to the other side of the island I saw a swallow or a swift, but I haven’t got the slightest idea what species it was.
I’m going to stick my neck way out here with the herons. Although two are very common on DG (the Striated and Cattle Egret), the Gray Heron is not common, if it is resident there at all. The reason I’ve included the Gray Heron in this section is that I personally saw several of them on DG in 1987 and 1988. Maybe someone reading this can confirm or deny that they are there now.
The easiest way to tell if a flying bird is a heron is the way it holds its neck and head, and the semi-circular shape of the wings (like a pair of those flat panel parachutes). Typically herons flap their wings slowly (the smaller they are, the faster their wings flap), with the neck retracted in a vertical S shape, and the head tucked back between the shoulders. This is characteristic of herons and bitterns (which don’t seem to inhabit DG), and distinguishes them from storks or cranes, which extend their necks out in front of their bodies while flying. By the way, if you see a stork or crane flying around, let me know!
Cattle Egret (Bubulcus ibis)
Known to the Ilois as “Madam Paton”.
The Cattle Egret is probably the most widespread and populous heron on earth. They easily adapt to just about any tropical or temperate environment. If you live in the Southern or Western U.S., you’ve seen them following cattle and tractors, and perhaps have even stumbled across a rookerie near water.
On Diego Garcia, the ones you see are probably hybrids of the African subspecies, which were intentionally introduced from the Seychelles in 1953, combined with some of the Asiatic subspecies had been blown down on the winter monsoon as early as the 1880s.
This is a small, chunky white heron, with a wingspan of about three feet. As with most herons (and as opposed to cranes) they fly with their necks curved in an S-shape, and their heads tucked in between their shoulders. It has a relatively short, thick, orange-yellow, pointed bill, yellow legs, and entirely white plumage, except during the breeding season. At that time, it develops some buff colored feathers around the head and shoulders, while the bill and legs turns deep red.
Unlike other herons, Cattle Egrets don’t hang around water. You will probably see these egrets on the airfield, or other large, cleared areas like the soccer field or the lawns at the Plantation, where they can hunt for the insects which compose most of their diet. You may even see them following donkeys on the move across T-Site, catching the insects stirred up by the donkey’s passing.
During the breeding season, they form rookeries in trees or large shrubs on or very near fresh water, with a nest on just about every limb. The nests are made from sticks, and there are anywhere from one to five eggs laid per nest.
This species is considered a pest around airfields, where they show not the slightest regard for aircraft noise, and will fly directly in front of aircraft taking off or landing, creating the potential for tragic accidents. During intense aircraft operations on Diego Garcia, teams of airmen armed with shot-shells will patrol the airfield and shoot these 12-gauge equivalents of bottle-rockets in the direction of egret flocks to scare them away from the area. Apparently, the BIOT has approved more direct action and In 2006, an article about control of egrets on Diego Garcia in the USAF safety magazine "Combat Edge" reported that the island population of Cattle Egrets had been reduced to about 80 birds, which could only be accounted for by killing.
Striated Heron (Butorides striatus)
Known to the Ilois as “Manique”.
Also called the Little Green or Mangrove Heron.
This is the smallest heron resident on Diego Garcia. The Striated Heron is wide-spread indeed, from West Africa east across tropical Asia, the IO, and Pacific to the Americas. In the Eastern Hemisphere, it’s found as north as Japan, and south to Australia. It is found on just about every tropical island in its range, and is considered con-specific (i.e., one and the same) as the Green Heron of North America. If you’ve ever been in a swamp in the good ‘ol USA, you’ve probably seen these herons, and they look and act the same on DG.
This little heron is usually found where there are bushes over water – salt or fresh, it doesn’t matter. This bird has very short legs for a heron, and doesn’t wade for its prey. Instead it prefers to sit very still on a low branch, its head pulled in tight to its shoulders, staring into the water, waiting for a fish, pollywog, or insect to come close. It also will sit amongst rocks next to the water’s edge, camouflaged by brush if possible. Unless you are looking for these quiet, stealthy birds, the first time you know you are near one is when it finally gets too nervous to continue to sit still, and takes off like a shot, with a loud croak, that, quite frankly, always scares me.
Like other herons, it has a very long neck, and the prey doesn’t have to come too close for it to reach. One neat trick Striated Herons are reported to do the world over is use bait for their hunting. They’ll take a feather or dried leaf and drop it on the surface of the water to attract prey. In the Seychelles, they’ve been observed to use bread crumbs that tourists throw to feed the fish. Pretty smart.
These little herons are resident on DG, and not migratory birds. They build a platform nest of sticks in shrubs or trees, usually near water. They lay 2 – 5 eggs, and both parents incubate, brood and feed the chicks. The young don’t take long to leave the nest. The eggs take just 20 days to hatch, and the young leave the nest just three weeks later.
Although it is often called a Green Heron, it appears to be mostly dark grey when it’s sitting there on its low branch. It has a greenish-black cap, yellow skin around the eye, and a greenish back that is hidden by the dark wings. It has a lighter grey belly and yellow legs and feet. Its bill is stout, almost oversized, with a sharp point. Young birds aren’t as glossy as their parents, and are streaked with white, with greenish legs and feet. See the photos below for examples (the adult is on the left).
Gray Heron (Ardea cinerea)
I’ve included this heron in this list because I personally saw three on DG in one day in 1988 - one was at the borrow-pit south of the airfield, and two were in Turtle Cove. The only other record I found was from 1899, but this big heron probably visits Diego regularly, if it has not established residency.
The Grey Heron is the largest heron in the Eastern Hemisphere, standing over three feet tall, with a wing span of six and a half feet, and is the Eurasian equivalent of its close relative, the Great Blue Heron of North America. The Grey Heron is native to the temperate regions of Asia and Europe, and also West Africa and Madagascar. It migrates from the northern part of its range, but otherwise is a resident.
In color, it is grey above, and buff below. The head is white with a pinkish bill, and it has broad, black eyebrows, and a black feather crest on top of the head which drapes down the back of the neck some distance. If you’ve seen a Great Blue Heron fly, the Grey flies the same way, slow, with wing beats that move the body up and down. Like other herons, it flies with its head tucked into its shoulders.
There are four subspecies of Gray Herons. The Gray Herons on DG are most probably migratory vagrants from Eurasia. In Europe, Africa and western Asia the subspecies is A. c. cinerea, and eastern Asia, it’s A. c. firasa. If you find a dead one out there, be sure to get it to the Brit Rep so he can have it properly butchered, dissected, and positively identified!
If Grays have taken up residency on DG, you may be able to find a small rookery in some tall trees close to water. Gray Herons build a huge, bulky stick nest – sometimes they are mistaken for eagle nests. No other bird on DG will build this kind of nest, so if you see one, keep an eye out for the occupants, and stay away as much as possible. Large herons are easily driven off their nests and you wouldn’t want the young to suffer.
Oh, if you heard a loud croaking “AAAAAANNNKKKK”, it’s a Gray Heron. The picture below shows a Gray Heron in typical Heron-style flight - curved wings, and head tucked into the shoulders.
LAND BIRDSAll the land birds on Diego Garcia were introduced by man, or flew in from other islands. There are no 'native' land birds on Diego Garcia. There seems to be continuing straglers arriving every once in a while - in 1987-88, I noticed several "lost" birds on the island. On the way out to the plantation one day, I saw a hawk the size and coloration of an immature Redtail hawk, but with a shorter head and tail. It was in the company of a bunch of noddy terns and was flying through the trees beside one of the barachois. On another expedition to the other side of the island I saw a swallow or a swift, but I haven’t got the slightest idea what species it was. And as mentioned above, I saw Gray Herons regularly in those days.
Well, here's some land birds that managed to overcome all the odds and colonize the island, despite the best efforts of mother nature, and the British bird butchers (at least when it comes to our first selection):
Domestic Fowl (Gallus gallus)
Most commonly called chickens!
There are 8 chicks in this photo!Chickens were everywhere on the inhabited side of the island, but there were none over by the plantation until the Space Commandos snuck some over to the plantation and GEODSS Site in 1987, after which they were all over over there too! Also the chickens could really scare you at night, as they roosted in bushes and if frightened themselves would flop around and make a lot of noise you weren't expecting.
Here are Chickens (two hens and two chicks), a Common Mynah, and Madagascar Fodies (the males are in the red breeding plumage, the females look like sparrows). All the land birds of Diego Garcia hang together, when it comes to raiding picnics. Photo by Bob Ralph, 2002.
Here are some birds that were reported as positively released by man (according to Hutson in Atoll Research Bulletin No. 175):Cattle Egret (Ardeola ibis): Nine (9) of these birds were imported from the Seychelles and released in 1953. In 1971 the only nesting colony found (estimated to be 10 nests) was located in a large mango tree near the Plantation. In 1982 there were anywhere from a few dozen to a couple hundred; by 1987 they could be seen in flocks of 4 or 5 on the airfield, and by 2001 were a serious Bird/Aircraft Strike Hazard at the airfield, and the USAF would attempt to scare them away with shell crackers, harassment in their nearby rookeries, and shooting when all else failed.
Indian Barred Ground Dove (Geopelia striata): Reportedly 16 birds were brought to DG in 1962, and 12 were released. It can now be found all over the island.
Indian Mynah (Acridotheres tristis): Twelve were brought from Agalega island in the Seychelles and released in 1954 or 1955. In the early 1970s the SEABEES used to catch these birds, keep them in makeshift cages, and attempted to teach them to talk (with varying reports of success).
Indian Barred Ground Dove (Geopelia striata)
Known to the Ilois as “Turtur cocos”.
Also called the Zebra Dove.
Turtle Dove (Streptopelia picturata)
Known to the Ilois as “Turtur des iles”.
Also knows as the Madagascar Turtle Dove, Painted Dove, or Red Turtle Dove.
Indian Mynah (Acridotheres tristis)
Also known as the Common Mynah.
Madagascar Fody (Foudia madagascariensis)
Also known as the Red Fody.
Male Madagascar Fody in breeding plumage.