Bates's Weaver

Description 

12-14 cm  

The male's head is mostly a bright chestnut-brown  

Black lores  

Sharp line of yellow-fringed feathers on nape 

Small yellow collar separates the head from the rich olive-green upperparts (IUCN Red List)  

Narrow hindcollar  

The lower nape, underparts, tail, and upperwing are olive-green  

Paler edges on primaries  

Chestnut-colored central patch on chin with the rest of the chin black  

Black throat  

Chin and throat clearly demarcated from the breast, belly, thighs, and undertail-coverts that are bright yellow  

Flanks are yellow with a greenish wash  

Iris is dark brown  

Black bill  

Legs are blue-grey  

Females are similar to males in appearance except for the the chestnut-brown forehead, crown, cheek, and ear-coverts that are black and not chestnut  

Females have a yellow chin and throat instead of black like the males  

Juveniles look like the females except with with a pale-olive green head and a beak that is a pale horn-brown 

Life span 3.46 years (IUCN Red List) 

Habitat  

This bird has a narrow range that stretches across Cameroon, Gabon, and the Democratic Republic of the Congo (DR Congo) with specimens found in localities such as Lolodorf and Sangmelima (Hall and Moreau, 1962)

Lowland rainforest up to 900 m in Southwest, Western, and Southern Cameroon (Limbe to Mouloundou) 

Behavior 

Believed to forage either alone, in pairs, or in mixed-species flocks  

Forages under a canopy  

Uses bark-gleaning to forage for insects (IUCN Red List) 

Insectivore  

Moves in a zigzag manner on tree trunks like the Bar-Winged Weaver (Ploceus angolensis) that is found further south in Angola, the Democratic Republic of the Congo, and Zambia  

Other Information 

Vocal behavior unknown (Birds of the World) 

Little is known about the species' biology (Demey, 2007) 

A specimen exists at the American Museum of Natural History (Dowsett-Lemaire and Dowsett, 2000)

This species is listed as Endangered by the IUCN that recently assessed Bate’s Weaver in 2021. Experts believe that the population of this species numbers between 1,000-3,500 individuals and is in decline due to habitat loss. They also believe that up to five subpopulations may exist throughout the species’ range that could number less than 1,000 individuals (IUCN Red List). Its range is believed to encompass the Dja Faunal Reserve, the Douala-Edéa Wildlife Reserve, and the Bakossi National Park that are all located within Cameroon (Birds of the World).

This species has only been seen in nine sites within a narrow range that stretches from the foot of Mt. Cameroon in Limbe to Mouloundou near the border with the Republic of the Congo. Of these sightings, most of them occurred within Cameroon and the Gabon lowlands. 

Bate’s Weaver was first described by Richard Bowdler Sharpe in 1908 as Othyphantes batesi. The species was named after George Latimer Bates who was the collector. He collected a female specimen of the species near the Dja River on January 29, 1906. The precise area where he found the specimen is not known but the area is supposedly called Bitye and is located near the southwestern border of the Dja Biosphere Reserve. The name of the area is questionable since “Bitye” is also the way locals in the area pronounced the collector's name. During the same year, a second adult male specimen was collected near Kumangola. Both specimens were sent to the British Museum. 

In 1909, four more specimens of Bate’s Weaver were collected at Bitye and sent to the British Museum. Unfortunately, Bates did not see these birds alive since they were killed with bows and arrows. More specimens were collected at Lolodorf, Sangmélima, and the Dja River at Mouloundou near the border with the Republic of the Congo.  

In 1978, Bate’s Weaver was seen twice at Tissongo in the Douala-Edéa Forest Reserve.  

In 1979, a member of this species was seen at the foot of Mt. Cameroon (Demey, 2007). The bird was described as moving in a zigzag manner up a creeper-covered tree trunk (IUCN Red List). 

This species is exceptionally rare with the majority of sightings occurring the 1990s. In 1990, Bate’s Weaver was sighted twice near Mt. Kupe. Since then, Bate’s Weaver has only been seen twice in 1995 and 1996. 

In 1995, Bate’s Weaver was seen in the Dja Game Reserve in Somalomo near the northwest boundary with the Republic of the Congo. 

In 1996, this bird was seen in Shwani, 12 km from Somalomo (Butchart, 2007). 

Despite extensive surveys that were done in West and Southeast Cameroon (1998-2001) and at Mt. Kupe, Bate’s Weaver remains elusive to this day (Birds of the World).

Bate’s Weaver is thought to be dependent on lowland forests. However, this species has also been in seen in secondary forests and degraded forest edges which suggests that it has a certain degree of adaptability. Since this bird is known to use a technique known as bark-gleaning to forage for insects, this may put this bird in conflict with another bird in its range, Preuss’ Weaver (Ploceus preussi). This competition along with habitat loss may be putting more pressure on any populations that remain (IUCN Red List).

Bate’s Weaver has a narrow range (68,800 km²) that exists mostly in Cameroon. However, some experts, such as Dr. Françoise Dowsett-Lemaire, believe that it is possible that the species’ range extends even further into the Lobéké Faunal Reserve in southeast Cameroon (Dowsett-Lemaire and Dowsett, 2000). To see a distribution map for Bate’s Weaver, click here. 

The main threat to Bate’s Weaver is deforestation and habitat loss caused by the expansion of agriculture and selective logging. The rate of deforestation and habitat loss in Cameroon is very high. Between the years 2000-2019, 5.2% of forest cover was destroyed. If palm oil plantations continue to be established in Cameroon, they could lead to the further loss of thousands of hectares of suitable habitat needed for Bate’s Weaver to survive in Southwest Cameroon (IUCN Red List).

It is unknown why Bate’s Weaver is so rare. Experts, such as Demey (2007), theorize that it may be due to the loss of a habitat feature but, then again, this species was already rare when Sharpe first described the bird in 1908.

Order: Passeriformes  

Family: Ploceidae  

Genus: Ploceus  

Species: Ploceus batesi