Pied cormorant, Pied shag, Great pied cormorant
The Australian pied cormorant (Phalacrocorax varius ), also known as the pied cormorant, pied shag, or great pied cormorant, is a medium-sized member of the cormorant family. It is found around the coasts of Australasia. In New Zealand, it is usually known either as the pied shag or by its Māori name of kāruhiruhi. Older sources may refer to it as the "yellow-faced cormorant".
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Monogamy is a form of relationship in which both the male and the female has only one partner. This pair may cohabitate in an area or territory for...
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FlockingFlocking birds are those that tend to gather to forage or travel collectively. Avian flocks are typically associated with migration. Flocking also ...
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ColonialColonial animals live in large aggregations composed of two or more conspecific individuals in close association with or connected to, one another....
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe pied cormorant is predominantly black on its back and upper surface of the wings and white on the underside with males weighing approximately 2.2 kg and females 1.7 kg. It stands between 65–85 cm tall, with a wingspan of 110–130 cm. A small yellow patch between the bill and the eye on each side of the head is likely to have been the reason for the historical common name. It has large webbed feet which it utilises to pursue fish underwater, steering with half opened wings. The bird has a large hooked bill, green eyes with a blue eye ring and black legs and feet. The eyes have a special nictitating membrane for underwater protection. The pied cormorant can often be seen spreading its wings after diving to help dry the feathers, as it has inadequate waterproofing. This lack of feather waterproofing may help the cormorant spend longer underwater due to decreased buoyancy effects.
There are two recognized subspecies; Phalacrocorax varius varius (New Zealand) and Phalacrocorax varius hypoleucus (Australia) with slight variation in physical characteristics. Similar species include the black-faced cormorant (slightly smaller) and the little pied cormorant (substantially smaller).
Although typically found in marine habitat—sometimes solitary, sometimes in pairs, sometimes in vast flocks of hundreds or thousands—it is also attracted to inland waters, including lakes, deep and open wetlands, and rivers. In Australia, the birds can often be found at inland waterways while in New Zealand it prefers coastal areas close to its prey. Adult birds are sedentary and can often be seen roosting in trees, on rocks or logs in the water. The birds seem unaffected by variable salinity, turbidity and shoreline vegetation provided there are available perches.
The pied cormorant appears to feed largely (90%) on benthic fish 6–15 cm in length from waters less than 10m deep. King George Whiting juveniles are known to be eaten. Other dietary components (10%) are made up of crustaceans such as prawns and shrimp with some molluscs and cephalopods. It will dive both in shallow, still water and in rapidly moving currents. Typical dive times are around 40 seconds, with a recovery period of 10–15 seconds between dives although this is dependent on depth. The birds feed in deep and shallow waters (although shallow habitats are more productive) with flock densities in proportion to the prey abundance.
Hunting is typically performed as individuals (potentially to avoid kleptoparasitism), although larger groups can be observed when schools of small fish are close to the surface. Risk of predation by sharks and the abundance of food comprise a trade-off where the pied cormorant may choose to hunt in deeper waters where prey is less abundant if the risk is too high during warmer months when sharks are present more often. The deeper waters however require longer dive times and corresponding longer times at rest between dives on the surface.
The pied cormorant preferably breeds in small (<30 pairs) sheltered colonies (harbours, estuaries and lakes) with rarer occurrences on exposed coasts or islands, no more than 400 metres from the sea (or food source). Courtship behaviour is initiated by the male in close proximity to a future nest site. Wing waving by the male is conducted in silence while gargling can be a form of female recognition. The males can also hop up to 1 m in the air with both feet to attract female attention.
Nests are typically large platforms formed of sticks and foliage cemented with droppings averaging 80 cm in diameter on the ground or in trees. Males collect most of the nest material, while both sexes share construction tasks. The nests are used twice a year in Autumn and Spring by different breeding pairs. Some breeding occurs in summer and winter by young and inexperienced pairs.
Monogamous breeding pairs (from 2 years of age) lay eggs once a year with an average breeding cycle of 6 months. Clutch size ranges from 2–5 with an incubation period of 25–33 days. Egg and fledgling caring duties are shared by the parents. Chick rearing can take from 47–60 days with independence gained just over 3 months of age. Both sexes share feeding duties through incomplete regurgitation.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...