Friday, May 9, 2008

BOOBIES! (and other birds)

A recent holiday in the Galapagos was a long time personal dream, fulfilled. It is a truly remarkable place, especially for those of us who still believe in the theory of evolution! And for anyone else out there who does, I highly recommend a book called 'The Beak of The Finch' by Jonathan Weiner, if you haven't already read it. The wildlife on these tiny islands is a living lesson in evolution and quite spectacular. There are numerous species of birds and reptiles that are found nowhere else on earth. For this posting I am going to focus on a few of the birds we saw.

The iconic bird that is always associated with the Galapagos Islands is the Blue-footed Booby Sula nebouxii excisa. In fact this is one of the species of bird found on the Islands that does occur else where, although the ones found on the Islands are a separate sub-species. They are the least common of the three Boobies on Galapagos and nothing can quite prepare you for just how vivid the blue of their feet really is. The Blue-footed Booby fishes close to shore and we saw them a number of times diving into the water, around the boats in harbour. They nest on the ground and we were fortunate enough to see numerous chicks.

Why are they called Boobies? They have forward pointing eyes which provides them with stereoscopic vision, necessary to spot their prey with accuracy. The positioning of their eyes does give them a rather comical appearance, Booby comes from the Spanish word 'Bobo' which means clown or stupid! Not very nice! The courtship routines are also rather clownish with lots of waving of feet and odd dance manoeuvres.
The second species of Booby is the Red-footed Booby Sula sula websteri, I think this one was probably my favorite and one that we got some of the best views of. The Red-footed nests in the mangroves, not on the ground like the other species. It is a deep sea fishing bird and is found on the outer islands where the water is deepest. This is the smallest of the three species and as a result it is harassed the most by the Frigatebirds on its long journey back to shore to feed its young. This was the first Booby species we saw when we landed on Tower Island which was the first island on our trip.

The funniest thing is how they sleep, with their heads hanging down way below their feet, they look as though they should loose their balance and fall head first out of the bush, but they never do! There is a less common color morph of Red-footed which has a predominantly white body, these make up about 5% of the population, this, oddly, is the reverse of anywhere else in the world that these birds are found.

The third species of Booby is the largest, the Nazca Booby.The Nazca Booby Sula granti is striking because of its incredibly white plumage. It nests on the ground, laying two eggs, the first one to hatch will push its younger and weaker sibling out of the nest (obligate sibling murder) so the parents will only ever raise one chick per brood. This species too was not adverse to putting on a comic act for the cameras as you can see from the one perching on the sign in the picture. We also saw a courting pair delightfully collecting stones and giving them to each other during a rather elaborate, high-stepping dance.

The Nazca Booby fishes in deeper water than the Blue-footed but shallower than the Red-footed. OK, OK that is quite enough Boobies for now. (FYI one of the hottest selling tourist items on the Islands was a hat with 'I Love Boobies' emblazoned across the front of it!)

One bird that I was particularly keen to see was the Galapagos Flightless Cormorant Phalacrocorax harrisi. Of all the species of Cormorants in the world (depending on which books you read that ranges from fourteen to twenty-nine!) this is the only one to have evolved to the point of being totally flightless. Amazingly, when Darwin made his famous visit to the Galapagos he did not see one of them, one has to wonder how much more quickly he would have come up with his theory of evolution if he had! We had some excellent viewing of these intriguing birds on their nests which are large mounds built mainly of seaweed. Each time the male approaches the nest when the female is sitting on eggs he will bring a gift of another piece of seaweed which is added to the nest! We also saw an amazing interaction between between two Cormorants and a Sea lion where they were all in the water together and when ever the Sea lion disturbed small fish, the Cormorants would dive and grab them. After a few minutes of this they climbed out to dry their wings in the sun, giving us the opportunity to get a picture which clearly shows their stumpy little wings.

One of the most dramatic birds seen in the Galapagos is the Frigatebird, of the five species found worldwide, there are two species that occur on the Islands, the Magnificent and the Great. The Great Frigatebird Fregata minor male puffs out his vivid scarlet throat pouch and utters a delightful warbling call whilst spreading his enormous wings and swaying back and forth.

The demure female seems almost embarrassed by such a show of opulence and lowers her eyes and flutters her bright red eyelids - well look at him, how could she resist?!

As you can see, they also take up the same bizarre sleeping posture as the Red-footed Booby! Nesting Frigatebirds produce one egg but their nests are notoriously flimsy and often the egg, and sometimes the young chick fall out and perish.

A darker side of the the Frigatebird is its reputation as the pirate of the air. It is often referred to as the 'man-o-war bird' for its ruthless way of capturing boobies or tropicbirds as they are returning to land with a full crop of food
and hanging them by the tail until they regurgitate the meal which the Frigatebird then consumes! But ugly reputation apart, they are truly awesome when seen in flight. They have the largest wingspan to bodyweight ratio of any bird and make a truly dramatic sight in the air. We very often had one of them flying with the boat when we were underway, they would hang effortlessly over the boat, rarely flapping their wings at all.

Another fascinating bird is the Swallow-tailed Gull Larus fureatus, having grown up near the sea, it is hard to imagine that I would be talking about a beautiful seagull! But this one is spectacular and very unusual. It is the only gull in the world that hunts at night, its eyes are adapted for night vision with more rods than cones. The structure of its eye also enables it to pick up the bioluminessence of its food of choice - squid.

Another unique thing about this gull is the fact that when it is returning to its cliff nesting site at night it utters a type of clicking vocalisation which it is thought to be a primitive form of echo-location, similar to that of bats! Often after sunset as we were sitting up on the top deck of our boat we would see a ghostly shape gliding along in front of the bow, it was a swallow-tailed gull, looking for food.

Some other birds that deserve an 'honorable mention' include, the Short-eared Owl Asio flammeus, on the Galapagos a sub-species of this owl has evolved to hunt a small bird called a Storm Petrel by ambushing it as it enters its nesting site which is hidden in cracks in the lava, this is the only known example of this type of owl hunting on the ground, even more unusual, it hunts during the day.

When it comes to the fun factor, it is hard to beat snorkeling with the Galapagos Penguins Spheniscus mendiculus. It seems rather odd to find penguins on the equator, this species is related to the more commonly known Jackass Penguin. The Galapagos Penguin is small, about 30cm's tall.

Another notable species is the Hood Mockingbird Nesomimus macdonaldi. These birds are very gregarious and will apparently often land on visitors to the Islands, although we never saw them do it. There are four species of Mockingbirds on Galapagos and the Hood is the largest and the most carnivorous. They will often dispatch the previously mentioned weaker sibling of the Nazca Booby.

The Lava Heron Butorides sundevalli is found skulking on old lava flows along the shore. It is a small, grey heron that blends with the colour of the lava almost perfectly. One of them flew right up to me and stood less then six inches in front of me with no apparent fear at all. We also saw one working the edges of a small pond where a Sea lion was splashing around, every time the Sea lion disturbed something small in the water, the Heron would rush in and grab it. Great team work!

I could not possibly do a bird blog and not mention my all time favorite, the pelican. Where ever I go in the world, when I see a species of this delightful bird I can't help but smile. They are amazingly graceful in the air and very much at home on the water but ponderous and slow on land. The sub-species of Brown Pelican Pelecanus occidentalis urinator which occurs in the Galapagos is often seen fishing offshore with Brown Noddy Terns flying around it often the Terns will land on it to steal a small fish from the Pelicans prodigious beak when the opportunity arises.

Of course this does not anywhere near cover all the fabulous species of birds that can be seen on these amazing Islands. The most important being the Galapagos Finches. This was a lesson in frustration for me because none of the guides on the trip were able to identify the finches and so I cannot say for sure how many of them I saw! They were also virtually impossible to photograph as they were in constant motion. But as many birders would say 'oh well that is just an LBJ!' (A little brown job!)

Photo Credits - Dominick V

No comments: