THE SPOTTED SHAG

 

The spotted shag or pārekareka (Phalacrocorax punctatus) is a species of cormorant endemic to New Zealand. Though originally classified as Phalacrocorax punctatus, it is sufficiently different in appearance from typical members of that genus that for a time it was placed in a separate genus, Stictocarbo, along with a similar species, the Pitt shag. Subsequent genetic studies show that the spotted shag's lineage is nested within the typical shags.

The spotted shag was initially called the 'crested shag' by Johann Forster. He shot the bird while hunting with the English Naval Explorer James Cook during the second voyage of James Cook. Swedish naturalist Anders Sparrman was Forster's assistant, he described the spotted shag in 1786 as Pelicanus punctatus.^[2][3]

 

 French ornithologist Charles Lucien Bonaparte erected the separate genus Stictocarbo for it in 1855. It was later returned to its original genus.

 

 In 1930, the Stewart Island population was described as a separate species, the blue shag (Stictocarbo steadi), distinguished by its narrow rather than broad white stripe on its head and neck.^[4]

A 2014 molecular study by Kennedy and Spencer found that the spotted shag belongs to a clade of Old World cormorants. Its closest relative is the Pitt shag (P. featherstoni), and their common ancestor split from a lineage giving rise to the black-faced, pied and little black cormorants of Australia.^[5]

Juvenile, note spots on back and wings

The spotted shag is a medium-sized marine bird. They are usually between 64 and 74 centimetres (25 and 29 in) high and weigh between 700 and 1,200 grams (25 and 42 oz). Their bodies are very slim and they have a very distinctive black, decurved, double crest growing on their nape and their forehead. They have a long, slender, orange-brown coloured, hooked bill and yellow-orange feet. The feathers on their bodies are grey and blue. The adults have small black spots on their backs and wings, which gave them their name. Their irises are brown, while the ring around the iris is blue. They have a small patch of bare facial skin between their eyes and bill, which turns green-blue just before breeding season. Furthermore, non-

 

 breeding adults do not have crests^[6] and have paler underparts.^[7] The males and females do look very alike, there is almost no sexual dimorphism.^[8] However, the males and females can be told apart by their calls and mating behavior.^[7] Normally they do not produce much noise, only when they are at resting, roosting and nesting areas.^[9] When they produce sounds, it can be heard as loud grunts.^[7] Spotted shags usually fly in V-formation and it is hard to tell males and female apart. In flight, they look slender and pale, while their rump and tail look darker.^[7] It is hard to estimate the total number of spotted shags in New Zealand; estimates are between 10,000 and 50,000 breeding pairs (20,000 to 100,000 birds). In the past, the number of spotted shags has been limited by the availability of food, which caused an increase in number during the late 1980s.^[7]

In flight, in breeding plumage (note the double crests)

The spotted shag is endemic to New Zealand. It breeds only on the coastlines of New Zealand and some of the offshore islands,^[7][10] being mainly found on the South Island. High numbers can be found on the west coast and near Stewart Island, but they also inhabit some places on the North Island. During breeding, they can mostly be found on their breeding sites, but otherwise they are more dispersed to other coastal areas.^[7] Large colonies can be found around Banks Peninsula near Christchurch, and in a rocky outcrop named the 'Shag Rock' in Wellington Harbour.^[8] Phalacrocorax punctatus are locally common, with estimates of numbers nationwide varying from 10,000 to 50,000 pairs.^[11]

 

 This species prefers to nest on cliffs along rocky coasts where they occupy ledges or cracks, forming colonies of over a thousand birds.^[10] They seldom go into freshwater environments or enclosed estuaries (Heather & Robertson, 2000). Seaweed is often used in lining the nests, the foundation of which is made of sticks.^[12]

The spotted shag lays one to four (usually three) blue eggs with chalky covering, with both parents continuously guarding the chicks for about 30 days. Chicks do not leave the nest until they are at least 52 days old. They may breed all year round.^[13] When the spotted shag hatches, it is completely blind, naked and weak and has very poor coordination. They will beg their parents for food, but are not able to direct it. Between day 4 and 6, their eyes start to open and between day 7 and 11 their begging starts to become more directed towards the parent. They also become a lot stronger and they start calling loudly. Down starts to cover their body and is becoming thicker between day 12 and 17. Then, they also become more active and start flapping their wings. Between day 18 and 23, the chicks start to move more rapidly, though clumsily. By this time, the tail feathers have grown to about 1 cm. Between day 24 and 30, the 

 

 spotted contour feathers are developing on the top surface of their wings. Some chicks start to leave the nests. Between day 30 and 35, the birds have almost reached adult size, but the down is still covering their bodies. The contour feathers will appear between day 35 and 40 and will be complete between day 40 and 50. By this time, the tail is also fully grown and many birds will have left the nests to form small groups. 

 

 ^[14] Later in life, they will form monogamous breeding pairs. Breeding colonies can sometimes consist of even 700 pairs. These pairs lay 3 to 4 blue eggs and the tasks of incubation and the rearing of the chicks are shared.^[9] Both parents feed the young by the ordinary manner in the nest. The fast flight of spotted shags up to a cliff-side perch makes its approach to nest spectacular.^[15] After breeding, most spotted shags remain within 200 kilometres of their breeding grounds. They form large winter flocks of up to 2000 birds, often flying in long lines between their feeding and roosting areas.^[11]

 

 It is common to find red-billed gull hanging around the spotted shag colony. Also, it is easy to find that the gulls' nesting colony are built nearby. The fact is that after the young spotted shag have been fed, parents have to leave nests to find more food to raise their young shags. At this moment, gulls forthwith fly to the nest and standing on the edge of it, their whole manner and tone of voice convey the impression of swearing. The young immediately disgorge some of their food, which the gull promptly eats.^[16]

Queen Charlotte Sound, New Zealand

Spotted shags are able to feed up to 16 km offshore. Their main diet consists of small fish and marine invertebrates,^[9] but they barely affect the New Zealand fish stock.^[6] The birds catch fish by diving from the sea surface and propelling themselves underwater with their webbed feet. They dive for an average of about 30 seconds,^[6] usually resting on the surface for 10 to 15 seconds between dives.^[11] The longest dive ever recorded was 70 seconds.^[7] Spotted shags often carry some small stones in their gizzard, which might function as to grind food or to avoid unwanted gut parasites.^[7] Sometimes they may be seen fishing singly, but more often a number are seen together, fishing by long dives or following a shoal.^[12]

Some birds are accidentally caught by fishing nets and drown.^[7] Spotted shags might be affected by the lice species Eidmanniella pellucida (Rudow, 1869) and Pectinopygus punctatus (Timmermann, 1964) (Pilgrim & Palma, 1982). Furthermore, they might be affected by the following tick species: Carios capensis (Neumann, 1901), Ixodes eudyptidis (Maskell, 1885), Ixodes jacksoni (Hoogstraal, 1967) that only appears on the spotted shag and Ixodes uriae (White, 1852) (Heath et al., 2011). They also might carry the flea species Parapsyllus longicornis (Enderlein, 1901) (Part & Part, 1990). The spotted shag does not appear to be subject to significant predation and disease. A parasite that may affect it is Contracaecum spiculigerum, Eustrongylides sp.^[17]

The species is considered to be not threatened.^[18] However, although the species used to be prevalent in the Hauraki Gulf, their populations have undergone a significant decline in the last century.^[19] DNA analysis has recently indicated that the birds originating from the northern parts of New Zealand are genetically distinct thus increasing the concern over the continuing decline of the species in and around Auckland.^[19][20]

In 1988, New Zealand released a series of postage stamps devoted to the native birds of the country. The spotted shag was featured on the 60-cent stamp.^[8]

 

 

 

 

 

 

 

 

 Location of New Zealand, including outlying islands, its territorial claim in the Antarctic, and Tokelau

 

 

 

 

 

THE PITT SHAG

 

The Pitt shag (Phalacrocorax featherstoni), also known as the Pitt Island shag or Featherstone's shag, is a species of bird in the family Phalacrocoracidae. It is endemic to Pitt Island where its natural habitats are open seas and rocky shores. The bird with the color of a dark body, gray chest, yellow eyes and feet can be found in small groups in their breeding habitat or alone within 18 km from their territory searching for food. The species was close to extinction in 1905 but actions of conservation have been done ever since. The Pitt shag is threatened by habitat loss due to predation and climate change causing a decline from 1997 to 2012, but there is a recovery plan by the Department of Conservation.

 

A Pitt shag at Pitt Island

Members of the shag family belong to three groups, based on the color of their feet: black, yellow or pink. Outside New Zealand, the black-footed shags are better known as cormorants. The Pitt shag belongs to the yellow footed group. They are about 63 cm in length and weigh 650–1300 g, with a slim build. The Pitt shag has a yellow colored detail around the eyes, light gray at the neck and chest, and the rest of the head, back, wings and tail with shades of black and navy.^[2]

From the Spotted shag (Phalacrocorax punctatus), the Pitt shag became a subspecies.^[2] This representative of the shags in the Chatham Group was discovered by H.H. Travers in 1871. Buller dedicated the species to Dr Featherston, superintendent of the Province of Wellington at that time.^[3] The Spotted shag and the Pitt shag have been determined as a part of the Phalacrocorax genus considering a DNA study.^[4]

When apart from the group the Pitt shag is quiet, but during mating season males make noises of grunting, gargling and ticking while females remain silent.^[2]

Shags find food on their own, traveling up to 18 km from their territory to feed on mostly small fish and when possible snails, worms and crustaceans found flying over waters and shores.^[5]

From August to December, 2 to 3 year old Pitt shags gather in small crowds on the rocky shores and cliffs of the coast, protecting themselves against predators and weather. With up to 40 pairs of birds, nests are created out of small branches, plants and seaweed, and are eventually found with about 2 to 4 pale bluish-white colored eggs. Parents take turns incubating the eggs for about 30 days, once hatched a single parent will stay with the chicks for two weeks, then both parents will search and feed their chicks until they fledge at around 6 to 8 weeks.^[4]

The Pitt shag is native to the Chatham Islands in New Zealand, islands such as the Chatham, Pitt, Rangatira, Mangere, Little Mangere, Western Reef, Pyramid, Sisters, Murumuru, Castle, Rabbit, Forty Fours and Star Keys.^[5] On an island the bird is located along the coast, on rocky islets and over nearby waters where breeding and foraging takes place such as the Te Whanga Lagoon.^[4]

Apparently never a common species, it was reported as nearly extinct in 1905. The Department of Conservation does have a recovery plan for this bird.

The Pitt shag is claimed endangered^[6] due to its loss of breeding habitat and rapidly declining, small population. Studies show a record of 729 pairs found from 1997 to 1998, 547 pairs from 2003 to 2004, and 434 pairs from 2011 to 2012.^[5] With nests planted along coastal cliffs predators are not much of a concern, although Feral Cats, Black Rats, Brown Rats, Common Brushtail Possum and Weka are known to be possible threats. The threat of human activity is more evident as it causes climate change, leading to changes in their environment and resources. These activities include introduction of predators, bycatch in the fishing industry, bird hunting, and crayfish pots.^[5]

Conservation actions done specifically for the Pitt shag are not very apparent, although other works on the Chatham Islands have been done such as withdrawing sheep and cattle from the South East and Mangere Islands in 1961 and 1968, and fencing coastal habitats to avoid possible interference. Actions that are being considered are measuring the whole adult population with intervals of 10 years starting from the year a plan is created, and in each year study the pattern of two communities. Other plans include analyzing the effect of rock lobster fishing, additional fencing, continuous studying of the breeding and foraging of the bird, and withdrawing feral cats, Wekas, sheep, cattle and pigs concerning Pitt and Chatham Islands.^[5]

 

 

 

 

 

 

 

 Approximate distribution

  Range

(Chatham Islands, New Zealand, Oceania)

 

 

 

 

THE LITTLE PIED CORMORANT

 

The little pied cormorant, little shag or kawaupaka (Microcarbo melanoleucos) is a common species of Australasian waterbird, found around the coasts, islands, estuaries, and inland waters of Australia, New Guinea, New Zealand, Timor-Leste and Indonesia, and around the islands of the south-western Pacific and the subantarctic. It is a small short-billed cormorant usually black above and white below with a yellow bill and small crest, although a mostly black white-throated form predominates in New Zealand. Three subspecies are recognised. Until recently, most authorities referred to this species as Phalacrocorax melanoleucos.

 

In New South Wales

The species is known as the little pied cormorant in Australia, and as the little shag or by the Māori name of kawaupaka in New Zealand. The term white-throated shag is also reserved for the melanistic form there.^[2]

  

 In India

The little pied cormorant was originally described by French naturalist Louis Pierre Vieillot in 1817. In 1931, American ornithologist James Lee Peters was the first to consider this in a separate genus along with the pygmy cormorant (M. pygmaeus), little cormorant (M. niger), and the long-tailed cormorant (M. africanus). Since then, molecular work by Sibley and Ahlquist showed the little pied and long-tailed cormorants formed a group which had diverged early on from other cormorants. This group of "micro-cormorants" assumed the genus name Microcarbo, initially described by French naturalist Charles Lucien Bonaparte in 1855.^[3] The generic name is derived from the Ancient Greek mikros "small", and Latin carbo "black". However, most older authorities refer to this species as Phalacrocorax melanoleucus.

 

 

In the now-extinct Waray language spoken along the Adelaide River in North Arnhem Land, the species was known as mawa.^[4]

Wing drying pose

The little pied cormorant is a small cormorant measuring 56–58 cm (22–23 in) with a shorter 3 cm (1.2 in) bill and longer tail than the little black cormorant; it has a small black crest. It is found in two morphs in New Zealand. Subspecies melanoleucos and brevicauda are found only in a pied morph, black (with a slight green tinge) above and white beneath. This is also found in subspecies brevirostris, but in this form the melanistic morph is much more common. In this form the entire plumage is black with a greenish tinge except for the sides of the head, chin, throat and upper neck; the bill is yellow with black on top. Intermediate forms are also found.^[2]

 

 

The pied form is glossy black above with white face, underparts and thighs. The bill and bare skin around the face are yellow. In both forms the legs and feet are black.^[5] The pied form is rare in New Zealand, and is most common there in Northland, where it makes up one in every four birds or so.^[2]

Chicks have dark brown down, with pied morph having patches of paler down. Immature birds are a dull blackish brown, with pied morph birds having paler underparts.^[2]

The little pied cormorant makes a low cooing during courtship.^[2]

Similar species include the black-faced cormorant (slightly larger) and the Australian pied cormorant (substantially larger).^[6]

The species ranges across New Zealand, from Stewart Island to Northland,^[2] and across mainland Australia (although not in the arid interior of the west of the country) and Tasmania. It is also present in Papua New Guinea, Palau, Timor-Leste, the Solomon Islands, New Caledonia, and Vanuatu. In eastern Indonesia, the little pied cormorant's range includes Sulawesi, the Lesser Sunda Islands, Maluku Islands, and Western New Guinea, with non-breeding birds recorded in Java, Bali, and once off the coast of East Kalimantan.^[5] Widespread and common, it lives near bodies of water such as swamps, lakes, lagoons, estuaries and the coastline.^[2][5]

The little pied cormorant is a benthic feeder, i.e. it finds its prey on the sea floor. It is a solitary feeder, normally diving in relatively shallow water, often near the shore. Dive times are short, around 15 to 20 seconds, with recovery times on the surface of 5 to 10 seconds unless prey are being swallowed. It takes a variety of fish prey but an unusually high proportion (nearly 30% by weight on average, and up to 80% in some individuals) of crustaceans. In New Zealand waters it is most often seen preying on the local flounder and other small flatfish. Eels and insect larvae are also consumed. These are brought to the surface to be swallowed: the bird will sometimes put a fish down on the surface of the water in order to re-orient it and swallow it head first. Because of this habit, they suffer some kleptoparasitism from red-billed gulls.

Breeding occurs once a year in spring or early summer in southern areas of its range (southern Australia and New Zealand), and after the monsoon in tropical regions.^[7] The nest is a platform built of branches and sticks, often still green with leaves in the forks of trees, usually eucalypts that are standing in water. Nests are often located near other waterbirds such as other cormorants, herons, ibises or spoonbills. Four or five pale blue oval eggs measuring 46 x 31 mm are laid. The eggs are covered with a thin layer of lime, giving them a matte white coated appearance. They become increasingly stained with faeces, as does the nest, over the duration of the breeding season.^[8]

 

 

 

 

 

 

 Range of the little pied cormorant

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

THE DOUDLE- CRESTED CORMORANT

 

The double-crested cormorant (Nannopterum auritum) is a member of the cormorant family of water birds. It is found near rivers and lakes and in coastal areas and is widely distributed across North America, from the Aleutian Islands in Alaska down to Florida and Mexico. Measuring 70–90 cm (28–35 in) in length, it is entirely black except for a bare patch of orange-yellow facial skin and some extra plumage that it exhibits in the breeding season when it grows a double crest in which black feathers are mingled with white. Five subspecies are recognized. It mainly eats fish and hunts by swimming and diving. Its feathers, like all cormorants, are not waterproof, and it must dry them out after spending time in the water. Once threatened by the use of DDT, the numbers of this bird have increased markedly in recent years.

The double-crested cormorant was described by René Primevère Lesson in 1831. It was formerly classified in the genus Phalacrocorax, but a 2014 study supported reclassifying it and several other American cormorant species into the genus Nannopterum.^[3] The IOC followed this classification in 2021.^[4]

Its scientific genus name is derived from the Greek words νᾶνος  : nános, "small" and πτερόν : pterón, "wing". This genus name was originally coined for the flightless cormorant (N. harrisi), which does have very small wings; although the double-crested cormorant has normal-sized wings, it (along with the neotropic cormorant, N. brasilianum) was still reclassified into the genus Nannopterum when the relationship between it and the flightless cormorant became apparent. The species name is from the Latin auritus, "eared", referring to its nuptial crests.^[5] Its common name refers to the same nuptial crests.

Close-up of an adult in breeding plumage with dark crests

The double-crested cormorant is a large waterbird with a stocky body, long neck, medium-sized tail, webbed feet, and a medium-sized hooked bill. It has a body length of between 70 and 90 cm (28 and 35 in) long, with a wingspan of between 114 and 123 cm (45 and 48 in).

 

 

This species has dark-colored plumage with bare supra-loreal skin and gular skin that is yellow or orange. An adult in breeding plumage will be mostly black with the back and coverts being a dark grayish towards the center. Nuptial crests, for which the species is named, are either white, black or a mix of the two. These are located just above the eyes with the bare skin on the face of a breeding adult being orange. A non-breeding adult will lack the crests and have more yellowish skin around the face. The bill of the adult is dark-colored.^[8] The double-crested cormorant is very similar in appearance to the larger great cormorant, which has a more restricted distribution in North America, mainly on the Canadian maritime provinces; it can, however, be separated by having more yellow on the throat and the bill.^[10] The neotropic cormorant also looks very similar, and the two species can sometimes be found together where their ranges meet.

 

 The plumage of juvenile double-crested cormorants is more dark gray or brownish. The underparts of a juvenile are lighter than the back with a pale throat and breast that darkens towards the belly. As a bird ages, its plumage will grow darker. The bill of a juvenile will be mostly orange or yellowish.^[8]

A very common and widespread species, it winters anywhere that is ice-free along both coasts, as far north as southern Alaska (on the west coast) and southern New England (on the east coast). It can be found as far south as Mexico and the Bahamas. It migrates from the coldest parts of its breeding range, such as eastern Canada, and has occurred in Europe as a very rare vagrant, for example in Great Britain, Ireland, and the Azores.

It is resident on Pacific Coast from Aleutian Islands south to Nayarit, Mexico (but excluding parts of British Columbia and the Southern California Bight) and inland to the Colorado River, resident on Atlantic Coast in Long Island and surrounding areas, southern New England, Florida, Cuba, and Yucatán Peninsula. Its breeding range extends north throughout most of north-central North America, from Utah north to Alberta east through the Great Lakes states to Nova Scotia, and south to northern Massachusetts, along with parts of Alaska adjoining Bristol and Kuskokwim Bays. Its nonbreeding range extends throughout all coastal plains in the US, including the Atlantic and Gulf Coastal Plains south to Campeche, as well as the Bahamas, Turks and Caicos, Hispaniola, and Cayman Islands, along with all areas previously stated to be resident. On the Pacific Coast, range includes all areas previously mentioned to be resident, along with British Columbia and the Southern California Bight.^[11]

Displaying,California

The double-crested cormorant swims low in the water, often with just its neck and head visible, and dives from the surface. It uses its feet for propulsion and is able to dive to a depth of 1.5–7.5 m (4 ft 11 in – 24 ft 7 in) for 30–70 seconds. After diving, it spends long periods standing with its wings outstretched to allow them to dry, since they are not fully waterproofed. This species flies low over the water, with its bill tilted slightly upward, sometimes leaving the colony in long, single-file lines.

Food can be found in the sea, freshwater lakes, and rivers. Like all cormorants, the double-crested dives to find its prey. It mainly eats fish, but will sometimes also eat amphibians, crustaceans and insects.^[7] Fish are caught by diving under water. Smaller fish may be eaten while the bird is still beneath the surface but bigger prey is often brought to the surface before it is eaten. Double-crested cormorants are also considered pests to aquaculturists because of their intense predation on fish ponds which can cause thousands of dollars in losses to farmers. Cormorants regurgitate pellets containing undigested parts of their meals such as bones. These pellets can be dissected by biologists in order to discover what the birds ate.

Parent and a chick at the nest

Breeding occurs in coastal areas as well as near inland rivers and lakes. They build stick nests in trees, on cliff edges, or on the ground on suitable islands. They are gregarious birds usually found in colonies, often with other aquatic birds, and have a deep, guttural grunt call.

The double-crested cormorant's numbers decreased in the 1960s due to the effects of DDT. Colonies have also been persecuted from time to time in areas where they are thought to compete with human fishing.

Recently the population of double-crested cormorants has increased. Some studies have concluded that the recovery was allowed by the decrease of contaminants, particularly the discontinued use of DDT.^[12] The population may have also increased because of aquaculture ponds in its southern wintering grounds. The ponds favor good over-winter survival and growth.

  

 Adult in breeding plumage with white crests

In 1894, Thomas McIlwraith in his book, Birds of Ontario, concludes his section on double-crested cormorants by saying: "When the young are sufficiently grown, they gather into immense flocks in unfrequented sections, and remain until the ice-lid has closed over their food supply, when they go away, not to return till the cover is lifted up in the spring."

 

 

For populations nesting in the Great Lakes region, it is believed that the colonization of the lakes by the non-native alewife (a small prey fish) has provided optimal feeding conditions and hence good breeding success. Double-crested cormorants eat other species of fish besides alewives and have been suspected of contributing to the decline of some sport-fish populations in the Great Lakes and other areas.^[13]

 

 In light of this belief, and because of calls for action by the public, the United States Fish and Wildlife Service (the U.S. federal government agency charged with their protection) has recently extended control options to some other government entities. This includes culling of populations and egg addling to thwart reproduction, in an effort to control their growing numbers. The U.S. Fish and Wildlife Service retains oversight and the control measures are not extended to the general public (no hunting season).^[14]

 

 In May 2008, the Canadian government reduced significantly the number of nests of the birds on Middle Island, a small island in Lake Erie and part of Point Pelee National Park.^[15] This is an attempt to keep the small island in balance and preserve its vegetation^[16] but opponents to the plan have argued that it is based on faulty information, provided in part by anglers who view cormorants as competitors.^[17] As of 2021, the cormorant culling program continues.^[18]

In 2020 the government of Ontario introduced a hunting season for double-crested cormorants from September 15 to December 31, allowing any hunter to kill up to fifteen birds per day.^[19]

Geographical distribution of Double-crested cormorant.

  Breeding

  Migration

  Year-round

  Nonbreeding