Lendu Crombec

Description 

Also known as Chapin’s Crombec 

This species’ defining trait is its chestnut cap that extends over the cheeks 

Top and sides of the head and nape are a rich chestnut-brown  

Mantle and back brownish with grey bases to feathers  

Rest of upperparts olive-green with grey feather bases  

Brown flight feathers that are fringed with a bright yellowish green  

Chin, throat, and midline of abdomen are white  

Rest of underparts are brownish grey  

Underwing-coverts, undertail-coverts, and thighs are lemon yellow  

Brown undertail  

Bill is greyish pink or flesh-colored that is dark or brownish below  

Irides is pale brown or chestnut  

Greyish pink or flesh-colored legs 

The Lendu Crombec is thought by many to be a subspecies of the White-Browed Crombec (Sylvietta leucophrys) that inhabits montane forests between 1,550-2,600 m and up to 3,000 in bamboo in some areas.  

This species has a wide range that extends throughout Burundi, Democratic Republic of the Congo, Kenya, Rwanda, Tanzania, and Uganda  

This bird is especially present in the highlands in Kenya, Mt. Elgon in eastern Uganda, the Kibale Forest in the west, and in the slopes of Rwenzori in both Uganda and the Democratic Republic of the Congo 

The main trait of the White-Browed Crombec are her white eyebrows that differentiate her from the Lendu Crombec whose eyebrows are covered by her chestnut cap 

Even though some variation can occur in head color among White-Browed Crombecs, the head is unusually richer and brighter on the Lendu Crombec (Fishpool and Collar, 2006) 

Habitat 

Montane tropical/subtropical forests and vegetation  

Other Information 

Life Spain- 5 years  

Breeding and vocal behavior unknown (IUCN Red List)

This species is listed as Critically Endangered by the IUCN that made its last assessment in 2016. Even though the population size was never quantified, it is thought to be extremely small (1-50 individuals), restricted to the Lendu Plateau, and in decline due to habitat loss. With no sightings since 1942, many believe this bird is extinct. Nonetheless, there are hectares of unexplored forest that remain to be explored. The species could still be living in these areas undetected. A major concern is that most of the montane forest habitat in the Lendu Plateau has been destroyed due to uncontrolled logging and encroachment from nearby villages. In 1994, only 24 hectares of forest remained. Thirty years later, the amount of remaining forest is probably significantly lower if not completely gone. 

For a distribution map for this species, click here.

The species was first described by Dr. Henri Schouteden in 1947 based on 3 specimens that were found in 1941 and 1942 by J.M Vrijdagh in the Lendu Plateau in the Democratic Republic of the Congo. These specimens were sent to the Royal Museum for Central Africa in Tervuren, Belgium. Schouteden described the bird as a distinct species and gave it the name Chapin’s Crombec. Ironically, the bird’s status as a distinct species was questioned by the very person she was named after. In the 1950s, J.P Chapin argued that the grayish underparts with yellow tibial feathers and undertail-coverts of the specimens meant that the bird was a subspecies of the White-Browed Crombec and not a separate species. His argument was so compelling that it continues to be widely accepted among the ornithological community to this day who treat the bird as a subspecies of the White-Browed Crombec.  

The only three specimens of the Lendu Crombec have been found in two areas in the Lendu Plateau in the northeastern Democratic Republic of the Congo (DR Congo). The Lendu Plateau is a large massif at the northern end of the Albertine Rift in northeastern DR Congo bordered in the north by Uganda. It is located between 1,700-2,000 m altitude with the main habitats being mostly grassland with isolated trees. Most of the montane forest above 1,500 m has been destroyed. However, this forest was very much alive when the first specimens of the Lendu Crombec were found by Vrijdagh in 1941 and 1942. The first and second specimens were found in Nioka (1,900 m) on July 24, 1941 and November 24, 1942. The last specimen was found in a forest near Djugu (1,800) in the valley of the Nizi River on November 26, 1942. According to Vrijdagh, the Lendu Crombec was common in the Lendu Plateau and behaved like other warblers from the Leucophorys genus where they foraged for insects on branches in dense undergrowth. Based on his reports, the Lendu Crombec was not exclusively a forest bird. The first specimen was found on the branches of a Eucalyptus tree outside a hotel in Nioka with the other two being collected in gallery forests (Fishpool and Collar, 2006). 

No sightings have been reported since 1942 with many believing the bird to be extinct.

The three main challenges that impede the survival of the Lendu Crombec are habitat loss, the bird’s dubious status as a species, and political instability in the region. 

The disappearance of the montane forests in the Albertine Rift is the biggest challenge facing the survival of the Lendu Crombec. Most of the montane forest in the Lendu Plateau has vanished due to encroachment from surrounding villages and logging. It is unclear how many patches of forest remain and if those patches are even sufficient enough to sustain a tiny population of Lendu Crombecs. Based on observations of White-Browed Crombecs in Kenya, warblers from the Sylvietta genus do not have much tolerance for disturbed and fragmented habitats. This does not bode well for the Lendu Crombec which is thought to be confined entirely to the Lendu Plateau and limited to a restricted area at the northern end of the Albertine Rift. One can only speculate since so much is still unknown about this bird. It is possible that this bird’s range could extend outside the Lendu Plateau, increasing her chances of survival. Some forests might still remain west of Lendu at Mt. Wago, around Mongbwalu, and Bondo Mabe that have not been explored. Without detailed surveys, it is unclear how the political instability in the Democratic Republic of the Congo has affected the rates of habitat loss in these areas. 

Ever since the species was first described, there has been disagreement over the species’ status. The majority in the ornithological community do not believe that the Lendu Crombec is even a distinct species and treat the bird as a subspecies of the White-Browed Crombec. This assertion was reinforced by a study in 2006 by L.D.C Fishpool and Nigel Collar who critically examined the only three specimens ever found of Lendu’s Crombec. They came to the tentative conclusion that the bird is indeed a subspecies of the more widespread White-Browed Crombec, "having had the benefit of being able to examine the skins, and whilst recognising that chapini differs strongly in head pattern and, to a lesser extent, colour--but in little else--we do not feel that such differences are sufficient to merit this treatment [distinct species] and prefer, on present evidence, to retain chapini provisionally as a distinctive subspecies of leucophrys." They contend that the head pattern of the Lendu Crombec can be seen in juveniles in other White-Browed Crombecs. They also admit that this status can change if more members of the Lendu Crombec species are discovered, their vocal behavior is better recorded, or a DNA analysis is done. Any of this evidence may prove that the bird is a distinct species. Until then, many will continue to believe and treat this bird as a subspecies of the White-Browed Crombec. 

Another challenge is the political instability that continues to plague the Democratic Republic of the Congo that makes any assessment or survey of the area almost impossible (Fishpool and Collar, 2006).

When the political situation in the region becomes stabilized, detailed surveys should be done to see how much forest remains in the Lendu Plateau and the Albertine Rift and whether or not any Lendu Crombecs could possibly still be living there despite the rampant habitat loss in those areas. 

Conduct a DNA analysis on the three specimens to see if there is enough genetic variance between the Lendu Crombec and the White-Browed Crombec to justify the former being treated as a distinct species.

The only known expedition to search for the Lendu Crombec was done from February 6-8, 1994. This expedition was led by Tommy Pedersen, Marc Languy, and Laurent Esselen. The three visited an isolated highland region west of Lake Albert in Lendu. Their mission was to find traces of the Lendu Crombec and Prigogine's Greenbul (Chlorocichla prioginei). By flying over the area, they were able to identify two main forest patches that had not been razed due to logging and encroachment from neighboring villages. These areas were Djugu close to the village of Nioka and another area close to the plateau’s edge east of Nioka. Each area was the size of around 10 football pitches. After searching both areas, they did not find any Lendu Crombecs. However, they did not come back empty handed because they were able to find 2 Prigogine’s Greenbuls (Pedersen, 1997). 

Thirty years later, it is unclear whether the forest patches searched by Pedersen and his friends still remain due to the high rates of logging and encroachment in the Albertine Rift. Political instability in the region makes any surveys next to impossible.

Order: Passeriformes 

Family: Macrosphenidae (formerly Sylviidae) 

Genus: Sylvietta 

Species: Sylvietta leucophrys chapini/Sylvietta chapini* 

*There is disagreement in the ornithological community concerning this species’ status. Some believe the Lendu Crombec is a distinct species but is extinct. Others believe that the bird is distinct and alive. The majority, however, consider the bird to be a subspecies of the White-Browed Crombec whether or not the species is extinct.