BIRDWALKERMONDAY

Wednesday, 9 June 2021

9-6-2021 CREU DE LONGA, ALBUFERA - LITTLE BITTERN (Ixobrychus minutus)

Little Bitterns were once widespread in Central Europe. In the meantime it is a poorly distributed breeding bird of the lowlands, sporadically up to low mountain ranges. It occurs from Europe (without regular breeding in Great Britain, Ireland or Scandinavia) to West Siberia up to 56° N. It also occurs in North Africa and southern Iran and south of the Sahara to southern Africa. Isolated populations also exist in Madagascar and Australia. The total population of Europe is about 60,000-120,000 breeding pairs, with occurrences of> 5000 breeding pairs in Russia, Ukraine, Romania and Turkey. In Central Europe (around 2000) about 5300-7800 pairs are breeding, most of it in Hungary. The formerly large population in Germany has decreased to just over 100 breeding pairs. However, inventory information is particularly unreliable for this very secret species.

The little bittern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds applies.

The little bittern is crepuscular, skulking and normally solitary. It feeds on fishes, amphibians and insects which are caught within reedbeds or at their edges by the bird slowly stalking the prey. The male claims a territory in the Spring, advertising his presence with a deep barking or croaking call and the monogamous pair remain together for at least one breeding season. Eggs are laid in a nest situated in dense reedbeds, rushes or bushes above the water from the middle of May and there is a single brood which is normally 5-6 eggs. These are incubated for 17–19 days and the chicks are fledged after 25–30 days.

In Europe the little bittern is a migratory species, crossing the Mediterranean from Africa in the early Spring and arriving in their breeding wetlands from mid April onwards. The return to Africa occurs in August and September and there are normally only a few juveniles left in Europe by October. The European breeders migrate as far south as the Eastern Cape and Transvaal.

The little bittern or common little bittern (Ixobrychus minutus ) is a wading bird in the heron family, Ardeidae. Ixobrychus is from Ancient Greek ixias, a reed-like plant and brukhomai, to bellow, and minutus is Latin for "small".

The little bittern has a length of 33–38 centimetres (13–15 in) and a wing span of 52–58 centimetres (20–23 in). It is the smallest of the breeding herons of Europe and is characterised by its tiny size, long and sharp bill and thick neck. The males are distinctively patterned and both sexes show pale forewing panels. The males have black with a faint green sheen on the crown, nape, back, tail and scapulars. The underparts are pale buff and the wing has a pinkish buff oval shaped panel which contrasts with the otherwise black wings and is formed by the inner wing coverts. The underwing is completely whiteish in colour. The female is duller than the male and has brownish black upperparts with paler feather margins visible at close range. The underparts of the female are not as clean as those of the male and are streaked with dark buff and brown. The female's wing panel is less obvious than the male's. The juveniles are duller and more rufous than the females and are more heavily streaked on both their upperparts and underparts, including their wing coverts.

The little bittern is native to the Old World, breeding in Africa, central and southern Europe, western and southern Asia, and Madagascar. Birds from temperate regions in Europe and western Asia are migratory, wintering in Africa and further south in Asia, while those nesting in the tropics are sedentary. It is rare north of its breeding range.

In Britain there were intermittent reports of breeding in the nineteenth century, and again in 1946 and 1957, but none of these records were proven. The first proven British breeding record is from Yorkshire in 1984, and the second from the Avalon Marshes in Somerset in 2010, by 2017 this species had been present in this area for nine consecutive years.

Minutus is migratory across most of its breeding range and has a significant post breeding dispersal. Birds in Europe move south in August–October. They fly singly and in small groups at night. Western birds move through Italy, Spain and France and along the Atlantic coast (Nankinov 1999). They cross the Mediterranean and Sahara in a broad wave. Birds from the east cross Israel, Iraq, Arabia, and Egypt, also in a broad front. Movement in Africa is less clear. Return migration is in March–April. Birds regularly overshoot and land north of the breeding range.

Minutus in the Middle East are partially sedentary. Minutus from north India, payesii and podiceps, are at least partially sedentary, with local movements that are not clearly understood. Payesii shifts in response to rainfall and drought. Podiceps is now understood not to migrate occasionally to Zanzibar as suggested by Brown et al. (1982). Dubius is probably migratory, shifting after wetlands dry out (March–April) from south to north and inland to coast, and also to south Papua-New Guinea. Return migration to the southern breeding areas in Australia is in August–September.

The Little Bittern ranges widely in post breeding dispersal, moving in all directions. Dispersal records include Iceland, Faeroes, Azores, Madeira, and Canary islands and Scandinavia. Dispersal records in the east include Lord Howell Island and New Zealand (O’Donnell and Dilks 1988).

Status: The species is widespread and common in many areas within that range. It has been decreasing in Europe, especially from 1970’s to 1990's, due to habitat loss (Nankinov 1999). Its nesting distribution is now fragmented, and the species appears to be in a rapid decline in west Europe (Marion et al. 2000). Its overall population is 37,000-107,000 pairs, the range reflecting uncertainties in eastern Europe - Romania, Ukraine, and Russia - which together support the greater portion of the European population (Marion et al. 2000).

The Little Bittern is common in north Africa, is increasing in Egypt (El Din 1992) and is more common in Arabia than previously appreciated. It has been under-represented on surveys in Tanzania; a guess at its population there puts it under 10,000 adults (Baker and Baker in prep.). It is rare in South Africa, under 100 pairs. It is uncommon in Madagascar and known from only a few places. It is abundant in parts of India (1,000-2,000 pairs in Kashmir). The population in New Zealand went extinct for unknown reasons – it is one of a few contemporary herons that has suffered extinction (Hilton-Taylor 2000). The Little Bittern is rare and very localized in Australia. It has declined in and west Australia due to habitat loss but may be more common in other areas than is presently appreciated (Jaensch 1989).

The habitat used by the species is varied across its huge range. Most typically it uses freshwater wetlands having thick herbaceous vegetation with trees or bushes interspersed nearby. These habitats include peat bogs, reed swamps, edges of lakes, pools, reservoirs, oases, swamps, wooded and marshy edges of streams and rivers, wet grasslands, mangroves, salt marshes, lagoons. In east Africa it prefers smaller, well-vegetated swamps, marshes and drainage ditches (Baker and Baker in prep.) It also can be found in forests. It occurs in lowlands and up to 1,500 m in Madagascar and 1,800 m in the Himalayas.

Typical herbaceous plants used in these habitats include Scirpus, Typha, Phragmites, Baumea, Juncus. Shrubs and trees used include Muehlenbeckia, Melaleuca. It uses human habitats including rice fields, ponds, crop fields, vegetable gardens, and sugar cane fields. Little Bitterns can be very tolerant of humans and nest in places regularly visited by people (Cempulik 1994).

The Little Bittern feeds by Walking slowly at the water edge stalking prey from the ground or more characteristically from a perch. It also Walks Quickly using Crouched posture, with head forward, in rapid steps. It Stands at the edge of cover on a perch. It feeds with its head and neck withdrawn. As it sees a prey item, it slowly extends its neck and then stabs. It sometimes it feeds by pecking, jabbing the bill in the water, and using an insect for bait (Baumann 2000).

It is a solitary feeder generally within territories held long term. Its activity periods appear to vary. It is primarily crepuscular over much of its range, but feeds at night and also at times during the day. African birds are primarily diurnal (Langley 1983). When alarmed it assumes the Bittern Posture.

The diet is varied, fish (Perca, Esox, Alburnus, Blicca, Cyprinus, Gambusia, Gobio, Eupomotis, Leuciscus), frogs and tadpoles (Rana), reptiles, eggs and young birds (Olioso 1991), shrimp, crayfish, worms, insects such as crickets (Gryllotalpa), grasshoppers, caterpillars, water bugs, beetles (Notonecta, Naucoris), beetle larvae, dragonflies (Libellula, Aeshna), spiders. Diet differs in various places. In some places it has primarily a fish diet (Langley 1983, Holmes and Hatchwell 1991) and in other places such as Italy insects predominate.

It is a small heron, roughly about the size of a pigeon. The back, top of the head and wing tips are black, contrasting with the rest of the plumage, which during the mating season in the male is creamy with some pinkish tones for the underparts and neck, and greyish cheeks. The latter tone being predominant in the female, although browner and the back is darker brown.

It is clearly present in the summer, as for the rest of the Iberian Peninsula, and the wetlands of Roquetas de Mar are one of its breeding grounds. Although it is most likely to be seen from May to July, during the postnuptial migratory passage and wintering, it is possible to spot it during this period, although it goes virtually unnoticed since it only leaves the reedbed in which it lives to feed on the edge, or in case of danger.

Despite the now annual handful of breeding attempts, the Little Bittern remains a rare visitor to our Britain.

This is a very small member of the heron family, about the size of a pigeon. Both sexes have a white wing panel, the male with black upperparts, the female brown. Little Bitterns migrate to Britain & Ireland in spring with most recorded from April. They return to Africa in the autumn.

The Little Bittern is a secretive and crepuscular species, which, together with the preferred reedbed habitat, makes this a very difficult species to observe and survey.