Pacific Biodiversity Institute invites avid birders to join a research expedition December 2-15, 2014, in the provinces of Salta and Jujuy in northwestern Argentina.
These provinces are renowned for their rich biodiversity and beautiful landscapes. They are ecologically diverse, with imposing mountains, extensive sub-tropical and tropical forests, rivers, canyons, deserts, salt flats and high lakes. The area is extremely rich in bird life, and other wild fauna and flora. Salta and Jujuy also contain some of the most colorful and vibrant culture in Argentina. Evidence of Inca and pre-Inca civilizations are found throughout the landscape. These provinces also contain some of the most important unprotected wildlands in Argentina.
The purpose of the expedition is twofold: 1) to gather more information about this region to aid in its further protection, 2) to introduce new people to this area of incredible contrasts, immense biodiversity, spectacular beauty and great conservation opportunity. Those interested in joining this trip may contact PBI at firstname.lastname@example.org. Further details can be found here: http://www.pacificbio.org/expeditions/salta_jujuy2014.html
Breeding in the Canadian Artic and wintering in Argentina and Chile, red knots undertake an epic migration journey of around 9,300 miles (15,000 km) twice every year. In order to complete the voyage successfully, red knots (Calidris canutus) require top quality food sources, and previously they have found this in abundance in the shape of horseshoe crab eggs in Delaware Bay. However, it’s been noted that red knot numbers have declined drastically since the turn of the century, with one of the main reasons being the decline in horseshoe crabs that have been harvested for commercial gain. Without sufficient fuel, these medium-sized shorebirds may not make it back to their Arctic breeding grounds, or if they do, they may be too weak to breed successfully, and considering that nearly 90 percent of the red knot population use Delaware Bay on their migration route, the lack of food could result in the species becoming endangered, or extinct.
Recognizing this problem, the US Fish and Wildlife Service (FWS) have proposed that red knots be classified as ‘threatened’ under the Endangered Species Act (ESA). Data reveals that there has been about a 75 percent decline in red knot numbers since the 1980s, with the rate of decline increasing sharply after the year 2000, coinciding with the decline in horseshoe crab populations. Red knots arrive at Delaware Bay just as horseshoe crabs arrive on the beaches to lay their eggs in shallow holes they dig in the sand. Each female lays up to 120,000 eggs in batches, which are then fertilized by the male that hitched a ride on her back to the beach. Shorebirds, including the red knot, eat many thousands of these protein rich eggs in the two week period before they hatch.
When red knots arrive at Delaware Bay, they are quite exhausted and emaciated. They need to rebuild their strength and stock up on fat reserves for the arduous journey ahead. As they feast on the eggs, they undergo a number of interesting physiological changes. As documented by the FWS, these include an increase in fat stores, and an increase in size of the chest (pectoral) muscles and heart, while the gizzard, stomach, intestines, liver and leg muscles of the birds decrease in size, all in preparation for the last leg of their migration.
While the decline of horseshoe crab eggs as a food source is a serious problem for red knots, it is not the only problem they face. The FWS notes that climate change is altering the terrain they breed in and impacting their diets on their home turf. Rising sea-levels and coastal development are other issues. But these are beyond the control of conservationists concerned with the plight of migratory birds. What can (and likely will) change is when harvesting of horseshoe crabs takes place, so that when the red knots arrive they have first choice of the horseshoe crabs’ eggs to fuel up for the last leg of their journey.
The Cattle Egret (Bubulcus ibis) is approximately 17 inches in length, with both sexes looking similar. They are predominantly white in color, with short, dull orange, pointed bills. In some rare instances, some adult birds might have deep red legs and bills, opposed to the dull yellow or orange that is generally found. Today, these birds are located world wide, but originated from Africa. It is suggested that they moved over the Atlantic ocean, from the African continent, and began a slow advance over areas such as South and North America, until they reached places like Argentina and Canada. Their migration over the world is so great, that they sometimes outnumber the native herons that are resident to a certain area.
Egrets spend their days in the company of cows, cattle herds or any livestock for that matter, relaxing and feeding in the wet pastures. They are constantly on the lookout for any beetles, grasshoppers or edible insects that are disturbed by the cow’s grazing. If the ground does not bring in enough food, they simply hop onto the backs of the cows’ and take a quiet tour around the field while searching for flies and ticks. After a days work, the Cattle Egret will fly up to the roosting accommodations to rest. They are also known to be birds of routine having daily routes which they follow. Egrets are commonly found amongst herons, and they are able to adapt to aquatic vegetation if cattle are not around.
Cattle Egrets nest in trees that are close to rivers or water, or wherever they are able to find vegetation to support their nests. Males will establish a territory, and then start with elaborate dances to attract a suitable female. Once a pair has been established, they head to a second location to build their nest together. Nest building is undertaken in a frenzied manner, with the male usually bringing the materials and the female doing the building. Materials are sometimes stolen from the neighbors, if their nest is left unattended. Nests are built in big colonies that include different species. The light blue eggs are laid with intervals of two days, and number between 3 to 4. Once all the eggs are laid, the male turns his attention to the nest. Both parents assist in the 24 day incubation period, and often need to shelter the eggs from the sun with their wings. Chicks will beg aggressively for food, but for chicks to kill each other is extremely uncommon. Adults will sometimes adopt other chicks if they are less than 14 days old. It takes between 14 to 21 days for the chicks to complete their growth, and although they are now able to leave the nest, they still remain close to their parents. It takes a complete 60 days for the Cattle Egret chicks to be able to fly and forage for themselves.
The Collared Plover (Charadrius collaris) is commonly found throughout the year in Mexico, Northern Argentina and central Chile, with a few being recorded in Guatemala. They are both coastal and inland birds, and frequent beaches, wetland areas, rivers and even ponds. Adult Collared Plovers are white on their bellies, with a black band across their chests. Male Collared Plovers have white on their foreheads with chestnut coloring on their midcrown and nape. Their legs are yellow in color and in flight, plumages are dark featuring a white wing bar. The females look very similar to their male counterparts, except for having a brown tinge to their black feathers.
These coastal and inland birds are extremely wary and are generally loners, very rarely being seen in flocks. They have a unique manner of scavenging for food, which is referred to as a run-and-pause technique. Most wader groups will use probing to find the insects and invertebrates, but the Plover prefers to keep moving, only stopping at intervals at the sight of movement. Nests are either built in the ground just above the tide line, or more inland. Female Collared Plovers lay two to four eggs at a time that are cream in color and have brown blotches. The males will engage in ground displays, to catch the eye of a suitable partner. Collared Plovers do not change plumage during or between breeding seasons.
As research has shown that the number of individual Collared Plovers is estimated at approximately 10,000, there is no cause for concern in regard to the conservation of the species. Due to the minimal decline in the population over ten years, these birds are not expected to reach the threshold of extinction any time soon. Conservationists are constantly monitoring the populations, but it is safe to say that these fast running birds will be seen along the shores for many years.
The impressively large and passive Wood Stork (Mycteria americana) is a waterbird that was formerly called the Wood Ibis, with the name change coming about because it is not actually an ibis at all. Wood Storks are the only stork native to North America and the only stork that breeds in this country, though they are generally found in the extreme southern parts of the country and their range extends as far south as Argentina in South America as well as into the Caribbean. Wood Storks are wetland birds and so they are commonly found near water sources such as swamps, marshes and ponds. They feed by wading in the shallows and eat small fish, tadpoles and crayfish. There is a small population which breeds in southern Florida, Georgia and South Carolina and it is this population which is considered to be endangered. However, those found between Mexico and Argentina are far more abundant and are not considered to be endangered.
Wood Storks measure around 85-115 cm in length, with a wingspan of 150-175 cm. They have long legs and are almost completely white in colour with a long, thick, down-curved bill. The head and top of the neck is black and bald and the white wings have black flight feathers. The tail is usually also black and their legs are peach in colour. Both sexes look alike and are capable of gliding for long periods of time. Juveniles are similar in appearance but with duller beaks and browner necks. Since they have no vocal muscles, they are fairly silent birds that only produce soft noises once in a while. It is interesting to note that they cool themselves off by urinating on their legs. When gliding, they are capable of diving and flipping, though they do look somewhat awkward when they flap their wings.
Nesting season for the Wood Stork is always dry. At this time of the year, lakes shrink and food is forced into smaller areas that are more easily waded. Because the catch is higher, the chicks stay well fed. At this time of year, these birds begin to make their nests in the top of tall trees. More than one bird may nest in the same tree and these birds usually nest in colonies called rookeries. The nests are made from moss, vines and twigs and hold 4-5 eggs. Incubation lasts about 30 days and usually only about two chicks survive the breeding season. The babies are fed by their parents for the first nine weeks during which time the parents take turns watching the nest and hunting for food. After this nine-week period, the juvenile Wood Storks are able to live on their own.