29 January 2011

Galapagos Wading & Water Birds

Many of the water associated birds we encountered on the Galapagos were long distance migrants, but there were also some resident species. We sighted Semi-palmated Plovers on numerous occasions. During July/August, 2010, I found this species breeding in the Pribilof Islands five to six thousands miles NW of the Galapagos.Striated Herons frequented the shorelines and potholes of most of the Galapagos Islands we visited. Some color morphs were once considered a separate species - Lava Herons - but DNA studies have determined otherwise.As their name implies, Flightless Cormorants are certainly not migrants, as they are the only species of flightless cormorants in the world. Cattle Egrets, apparently historically found in Africa, now seem to be found throughout much of the tropical and temperate world.Whimbrels have been present in many of the seaside locations I have visited in the past several years.One of the species I was especially interested in finding on the Galapagos was the White-cheeked Pintail. The only place we found them was on a volcanic pothole on Isabela Island. This species is also found in the Caribbean Islands, and it is unclear to me whether or not there is interchange between these populations.What can I say about Sanderlings? They seem to be present at some portion of the year on almost any ocean shoreline where I have visited in the Western Hemisphere. And we see them regularly during fall migration in Montana. American Oystercatchers were present on many Galapagos islands and we observed several nest sites and breeding pairs.Perhaps the target bird species that I was most anxious to observe was the Greater Flamingo. Having failed in several attempts to find them in the Florida Everglades where they occasionally occur, I was hoping my luck would change on this trip. After a half hour walk over some desolate lava flows on Isabela Island, we found four of them on a brackish water pothole. Their pink coloration in this mostly gray and black environment was striking, but fit in well with the Mangrove and other vegetation along the perimeter of the pothole. This species seems more like a tropical one so finding them in a near desert situation on Isabela Island was a real treat. In good precipitation years, their numbers are estimated at nearly 400. On at least one occasion, birds from this population have been observed on mainland Ecuador so there may be interchange with other populations in South America and the Caribbean.

24 January 2011

Land Birds of the Galapagos

The species variety of land birds on the Galapagos is quite limited which is to be expected because of the islands relatively young age and geographic isolation. But there were several species that were quite familiar to me. The first was the Vermilion Flycatcher that I have often seen in Arizona. There are also several records for this species in Montana. The bright red on the head and underparts were a welcome sight compared with the the drab colored and much more abundant Galapagos Finches. Another brightly colored species with which I am quite familiar was the Yellow Warbler, which is a common summer breeding species in Montana. The plumage of Galapagos yellow warblers is, however, a bit different from ours with the rusty cap being quite obvious. These birds are more similar to the "Mangrove" Yellow Warblers that I have seen in Mexico and they may be considered as a separate species pending DNA analysis.

Galapagos Finches - 13 species - were the most abundant land birds on the islands. Over many thousands of years, they all evolved from a single species as a result of isolation on various islands, elevational differences in habitat, and extremes of climate. They are all pretty much similar in plumage so the best way to differentiate them is by their relative size and the shape and size of their bills. This is a Small Ground Finch.Medium Ground Finch.Cactus Finches seemed to be fairly abundant.
But we found the Large Cactus Finch on only one island. There are 4 different Mockingbird species on the islands, three of which we observed. The forth species is found on an island that we did not visit. The Galapagos Mockingbird was the most common of this group and was found on a number of different islands.Hood Mockingbirds are found only on Espanola Island. They were extremely tame and often would investigate backpacks and other human items left on the beaches.Charles Mockingbirds were once abundant on Floreana Island but were extirpated by introduced rats and perhaps other non-native species. They are now found only on two small islets just to the west of Floreana where they can be viewed only from boats cruising around these islets.
We did manage to see and photograph several of them.

One of the more attractive of the native, endemic species is the Galapagos Dove. We encountered them on many of the islands but not in any abundance.

At the top of the food chain is the Galapagos Hawk. They are obviously descended from a Buteo type raptor that must have reached the islands many thousands of years ago.There was one relatively common introduced species that we saw on a number of occasions - Smooth-billed Ani. This species may pose a threat to some of the native species. It is unknown whether this bird arrived here on its own or was introduced by islanders, but it was most likely the latter.

23 January 2011

Galapagos Birds

The diversity of bird species on the Galapagos Island is not all that great, with only 70-80 species occurring on a regular basis, and another 30-40 seen only occasionally or rarely. But many of the species found there are endemic and are seen and breed only there. Others use the islands exclusively for breeding but may wander far and wide during the non-breeding season. In this first segment on birds, species associated with the surrounding ocean for their livelihood and land for breeding purposes will be featured.

There are two gull species endemic to the islands, Lava Gull and Swallow-tailed gull, that are only very rarely seen anywhere else. We did not see many Lava Gulls, perhaps because their coloration matched the lava dominated shorelines quite well, or maybe they just weren't very common. But Swallow-tailed gulls were observed often and were really quite an attractive bird - as gulls go. There are three species of "Boobies" that breed on the islands: Blue-footed, Nazca, and Red-footed. The first two were common but we never did see any Red-footed Boobies, although several hundred thousand of them breed on one on the islands in the NE portion of the archipelago. Nazca Boobies are very similar to Masked Boobies from other regions and may have been considered the same species at one time. Blue-footed Boobies were the most common and it is not difficult to see where they got their name. They were quite tame and many had young that were about to begin flying. Galapagos Penguins were not especially abundant but we found them on several different islands. They are the second or third smallest of all penguin species and the only ones found in the tropics. They likely found their way here many thousands of years ago on the cold Humboldt Current that flows north along the South American Coast from the Antarctic.
There are two Frigatebird species on the islands, the Magnificent and Great Frigatebirds. They are very difficult to tell apart, especially the males. This male is likely a Magnificant rather than Great because of the purplish sheen of its neck feathers. The Great males supposedly have a greenish sheen. Recent DNA studies have determined that the magnificent Frigatebirds on the Galapagos have been isolated from those located in other regions for about 100,00 years, so they may be separated into a different species in the future.

Another of the endemic seabirds of the islands is the Galapagos Shearwater. It ranges widely over ocean areas during non-breeding periods.
They were commonly viewed in offshore areas during our cruise.

The following are two species that I was especially interested in seeing - Waved Albatross and Red-billed Tropicbird. This albatross species breeds exclusively on several Galapagos islands but wanders the oceans during non-breeding periods. It apparently gets is name from the wavy pattern on the neck and breast. Note the band on the right leg of this bird.
We did not encounter many Red-billed Tropicbirds, but their very long central tail feathers made them easy to ID when they were around. In the volcanic cliff areas where they nested, these tail-feathers were often the only part of the birds that we could see.

09 January 2011

Frosty Day in Helena Valley

Winter weather in Montana can be a little bothersome sometimes. But there are usually a few days that make up for a lot of the cold, snowy, and cloudy ones. The third of January was just such a day. Our home on the south side of Helena lies several hundred feet above the valley floor. As the sun climbed into a gorgeous, deep blue sky that day, I looked out the picture window facing north and was disappointed to see that the lower portions of the valley were pretty much shrouded in fog. But I had been housebound for several weeks and really needed to get out to do some windshield birding. Days with dense fog can be frustrating for birding because of reduced visibilities, and indeed, I encountered some of that frustration on my drive into the valley that morning. But the upside to the fog, that had apparently persisted throughout the night, was a coating of white frost on essentially all inanimate and vegetative features over the entire valley. It was absolutely gorgeous! If I had thought to bring a good pair of boots along for walking in the snow, I would have concentrated on landscape photography that morning, but in my rush to get out of the house I forgot boots, so my usual pursuit of birds would have to suffice. To my surprise, there were birds about and they provided some rewarding opportunities for photos. The following images were ones I acquired that beautiful morning. My first encounter was with a prairie falcon that sat calmly on a power pole for a relatively close approach, an unusual case for this species. Next up, a dark phase rough-legged hawk flushed out of a cottonwood tree upon my approach, but didn't get far before my camera caught up with it. There is one side road where I frequently find a bald eagle perched this time of year, so I tured there to take a quick look. I was rewarded with an adult eagle sitting on the same old snag where I usually find one, and as a bonus, a female rough-legged hawk was perched nearby. At this point in the morning, the fog began to lift and the bright sun highlighted the frost encrusted vegetation so that it looked like fine embroidered lace. As I passed by a weedy field, I caught a glimpse of some small birds flitting among the stems looking for seeds to eat. They were American tree sparrows, a fixture in our valley in the winter, arriving early from their breeding areas far to the north. They are usually in small bunches, but as I stopped my vehicle, more and more of them appeared. There were dozens of them. Something made them nervous, perhaps me watching them, and suddenly they all flushed to a nearby caragana hedge. I backed up, stopped near the hedge, and did some "pishing" to try to coax them into the open. Slowly, several of them began to hop up to the higher branches of the shrubbery. During the next hour, I clicked the shutter of my camera perhaps a hundred times trying to get that perfect shot of one of these neat little sparrows - perched on a lace covered stem silhouetted against the clear blue sky.
That one great morning in the Helena Valley has quieted my need in the past week to venture out for some winter birding again. But I can feel that urge growing in me, so hopefully our new snow of today and falling temperatures will again combine to provide another of those memorable days. Sitting and looking at this computer all day just doesn't do it for me!

05 January 2011

Galapagos Island Mammals

Wildlife photography in the Galapagos is different from most other locations because the animals are so much more approachable. Historically, they had very few or no natural predators so when humans arrived, the land animals had no reason the be wary of them. The other side of this is that because of the islands' location and relative isolation, species diversity of land mammals, birds and reptiles is quite low. In fact, there are no native mammals on the Galapagos that are not associated with the surrounding Pacific Ocean except for several species of bats and rice rats, none of which we observed. Diversity of aquatic mammals and other vertebrates, especially fish, is considerably higher.

Given that background, the only mammals species I successfully photographed were Galapagos Sea Lions and several marine species. We saw Galapagos fur seals but they were not abundant and difficult to locate because they frequented volcanic caves and other shorelines features that were difficult to traverse. Sea lions were abundant mostly everywhere we went, and they were not only very tame but often inquisitive, especially when we were snorkeling. They would often swim up to people snorkeling and playfully almost nudge them with their noses. When resting or sunning themselves on shore, they were oblivious to people around them. Many of the young pups were still nursing their mothers. Other young adults were often seen playing with each other. On several occasions while cruising, we encountered large groups or pods of Bottlenose Dolphins, many of which put on pretty impressive acrobatic shows. On a number of other occasions, we saw whales that we could not identify, but could have been one of a half dozen species that are found in the region.

The most exciting encounter we had on the trip was with an Orca. As I was heading to the upper deck one morning, I hear some excitement from several folks who were already there. There was a single probable young male Orca near one of of Zodiacs that was ferrying some snorkelers ashore. The Orca swam up along side the Zodiac, not more than 15-20 feet from it, and followed beside it for several minutes. At one point, it submerged, caught a sea turtle, and surfaced with the turtle in its mouth. It would certainly have been great to be one of the lucky folks in that Zodiac, but I consider myself fortunate to have been able to get some reasonable photo images of this exciting event. This Orca was probably about 30 feet long and weighed in the neighborhood of 12,000 pounds.

Galapagos Scenery

The Galapagos Islands are all of volcanic origin, and for the most part, the climate is relatively dry even though they are located in the tropics. The exception to this is the highland areas on some islands that support a quite lush vegetative community. A complex of ocean currents around the island drive the weather patterns, with a warm and wetter season from December to May and a cooler, drier pattern from May through November. The weather patterns spawned by "El Nino" events in the Pacific Ocean result in occasional very wet periods, and extreme droughts are also rather frequent. These events combined with the geographic isolation of the Galapagos are the major influences on the island vegetation and wildlife.

Our island visits were all by foot except for some vehicle travel to higher elevations on Santa Cruz Island, so most of the scenery and vegetation we encountered was on the dry end of the spectrum and dominated by volcanic features. This view from a high point on Bartolome' Island is a great example of some different forms of a volcanic landscape. Lava flows were common on many of the near shore areas. At higher elevations, lava tubes were formed when the outside portions of lava flows cooled and solidified allowing the molten interior to continue moving until only a hollow area remained. Large sinkholes also developed at higher elevations when the levels of lava beneath them receded. Other areas were stable enough to support lush vegetation that in some places are now used as cattle pasture. Five of the 19 larger islands have human habitation, with Puerto Ayora on Santa Cruz Island being the largest at about 20,000 people. The Galapagos National headquarters and the Charles Darwin Research Station are located there. A tortoise breeding facility is housed there to provide young tortoises for efforts to restore them to islands where their populations have been decimated or extirpated by man and introduced predators such as rats. Feral goat populations also competed for forage and over grazed many landscapes. Puerto Ayora is the center of the tourism industry on the islands and supports a small commercial fishery. That is a very brief discourse on the islands, and as you can see, the scenery is dominated by volcanic features and dry vegetative communities. Learning about and experiencing the unique plants/vegetative communities and wildlife species found no where else on earth were my goals for this adventure and I'll blog about them over the next several weeks.