Australasian grebe

Tachybaptus novaehollandiae

Photo by J.J. Harrison (Wikipedia)

Common name:
Australasian grebe (en); mergulhão-pequeno-australiano (pt); grèbe australasien (fr); zampullín australiano (es); Australischer zwergtaucher (de)

Taxonomy:
Order Podicipediformes
Family Podicipedidae

Range:
This species is found throughout  Australia, in southern Indoneasia, New Guinea, the Solomon islands, Vanuatu, New Caledonia and recently colonized several areas in New Zealand.

Size:
These birds are 23-27 cm long and have a wingspan of 39-40 cm. They weigh 100-230 g.

Habitat:
The Australasian grebe is found in various inland wetlands, such as marshes, swamps, ponds, lakes and small reservoirs, preferring shallow areas with floating vegetation. They are found from sea level up to an altitude of 1.000 m.

Diet:
They feed mostly on small fishes, aquatic insects, spiders, crustaceans and snails, but will also take some seeds and other vegetable matter. They are also known to occasionally eat frogs.

Breeding:
The breeding season of the Australasian grebe is variable and possibly stimulated by flooding. The nest is a small floating platform of vegetable matter, placed among emergent vegetation. The female lays 4-5 pale blue eggs which are incubate by both parents for 23 days. The chicks are able to swim from birth and are cared for by both parents for 8 weeks. They may not yet be able to fly when they become independent. Each pair can raise up to 3 broods per year.

Conservation:
IUCN status - LC (Least Concern)
This species has a very large breeding range. The overall population trend is increasing, although some populations may be stable and others have unknown trends, and some of the smaller island populations may be at risk due to habitat changes such as the drainage and exploitation of underground water supplies.

Great crested grebe

Podiceps cristatus

Photo by Ken Billington (Wikipedia)

Common name:
great crested grebe (en); mergulhão-de-crista (pt); grèbe huppé (fr); somormujo lavanco (es); haubentaucher (de)


Taxonomy:
Order Podicipediformes
Family Podicipedidae


Range:
This species is found across most of Europe and central Asia, wintering also in southern Asia. There are some scattered colonies in Africa, from Tunisia and Egypt in the north, through a few colonies in central Africa and into South Africa. There are also nesting colonies in southern Australia and New Zealand, with individuals wintering in eastern and northern Australia.


Size:
These birds are 46-51 cm long and have a wingspan of 59-73 cm. They weigh 0,8-1,4 kg.


Habitat:
Great crested grebes are mostly found on fresh or brackish waters with abundant emergent and submerged vegetation, showing a preference for non-acidic eutrophic waterbodies with flat or sloping banks and muddy or sandy substrates, and with large areas of open water. They are can also be found in swamps, saltpans, estuaries and reservoirs.


Diet:
They eat fishes, aquatic insects, amphibians, crustaceans, spiders and seeds.


Breeding:
The breeding season of the great crested grebe varies between different parts of its range, occurring in April-September in Europe and Asia, all year round in Africa and in November-March in Australia. The nest is a platform of aquatic plant matter either floating on water and anchored to emergent vegetation or built from the lake bottom in shallow water. The female lays 3-4 eggs which are incubated by both parents for 27-29 days. The chicks leave the nest soon after hatching and are often carried around on the backs of their parents, fledging 71-79 days after hatching.


Conservation:
IUCN status - LC (Least concern)
This species has an extremely large breeding range and the global population is estimated at 920.000-1.400.000 individuals. The overall population trend is uncertain, as some populations are decreasing, while others are increasing or have unknown trends.