Sassi's Greenbul

Description

Also known as Sassi's Olive Greenbul

15-16 cm tall

Small Greenbul with a distinctive black crown

Black crown varies from bold to faint

Ornithologists theorize that the black crown is gained through maturity (Fishpool, 2006)

Lores and ear-coverts are a dull olive with a faint dark streaking on the ear coverts

Narrow olive eye ring

Obscure yellowish line in the front of the eye

Olive brown forehead

Forecrown to nape is mottled black and olive in color

Upperparts are a dull, dark olive-brown

Uppertail-covers are slightly rufous

Dark, reddish-brown tail

Blackish-brown wings

Outer margins of primaries are a light, greenish-brown

Bend of the wing is olive-yellow

Olive yellow throat

Underparts are a dirty, yellowish olive-green

Center of stomach is a paler olive-yellow

Undertail-coverts are brownish-yellow

Females are smaller than males on average

Average life span 4.5 years (IUCN Red List)

Habitat

This species is located in scattered locations across the Northeast and Eastern regions of the Democratic Republic of the Congo. There are also accounts of the bird being in Western Uganda (Bwamba)

The Sassi's Greenbul's range coincides with that of the Icterine Greenbul that has a much wider range across several African countries such as Angola, Cameroon, Central African Republic, Democratic Republic of the Congo, Côte d'Ivoire, Equatorial Guinea, Gabon, Ghana, Guinea, Liberia, Nigeria, Sierra Leone, Tanzania, Togo, and Uganda (IUCN Red List)

Prefers primary forest at an altitude between 600-1580 m

Moist lowlands

Traditional tropical and subtropical forests

Savanna

Classified as a restricted-range species

Very scarce (IUCN Red List)

Behavior

Insectivore

Gathers in small groups and mixed-species flocks

Other Information

The diet, breeding behavior, and sounds of the Sassi's Greenbul remains unknown (Birds of the World)

The population size of Sassi's Greenbul remains unknown (IUCN Red List)

Sassi's Greenbul is listed as Least Concern by the IUCN Red List because the species has a large range and does not meet the criteria for being classified as Vulnerable. The population is thought to be decreasing due to habitat loss but not to the point of being threatened according to the data available. The IUCN made its assessment in 2016 (IUCN Red List).

The IUCN's designation for Sassi's Greenbul as Least Concern is misleading. This does not mean that the species is safe but, rather, that the IUCN has insufficient data to prove that it is otherwise. Since the IUCN's assessment, there has been an increase in rates of habitat loss and climate change. Because little is known about Sassi's Greenbul, the IUCN's assessment is based on the little data that it has on hand. This makes this species a conservation concern because Sassi's Greenbul may be endangered and no one would know because of how little is known about this species.

Since the species was first described in 1914, Sassi's Greenbul is purported to inhabit these areas in the Democratic Republic of the Congo based on the sites where specimens were collected:

Eastern Zaire Lowlands EBA (Endemic Bird Area) in the Kibali-Ituri district that includes Bondo Mabe, Irumu S, and Beni)

Semliki Forest

Ituri Forest

South Kivu from Hombo west of Mt. Kahuzi

Kamituga, Itombue

Bambesa in Uele district

Kahuzi-Biéga National Park

Okapi Faunal Reserve

Mount Hoyo Reserve (Birds of the World)

Forests west of Lake Edward

Lowlands of the Itombue Mountains

Bondo-Mabé

Etäetu

Lima

Djuma

Manzali

Hombo

Lukigi

Itabe

Migamba

Kiloboze

Kakanda

Nyabisanda

Kanyaa

Mandza

Lumbokwe

Kiliza

Mwenge

Kitongo

Mbutanda

Simbo

Moera (the first specimen was found here)

Ukaika (Fishpool, 2006)

Semliki National Park in Uganda also lies within this species' range (Data Zone-Birdlife International)

Ntandi in Semliki National Park (IUCN Red List)

To see a distribution map for Sassi's Greenbul, click here.

In February/March 1996, Andrew Plumptre and his team, while conducting research into the effects corridors of disturbed forest have on endemic species in the Okapi Reserve within the Ituri Forest in the Democratic Republic of the Congo, caught three Sassi's Greenbul through mist-netting. Plumptre even took a picture of his encounter with the bird. This photo is perhaps the only photographic evidence of the bird alive outside photos taken of museum specimens. According to the study he published a year, Plumptre says he caught the greenbuls at a site called Apharama, 25 km north of the Trans-African Highway at an elevation of 800 m, that is known to have a mature, mixed forest (Plumptre, 1997).

You can see the photo he took of the Sassi's Greenbul here.

The main threat Sassi's Greenbul faces is habitat loss as more understory trees are cleared to make way for cocoa plantations.

There is expanding rice cultivation taking place near Semliki National Park in Uganda. This is a national park where Sassi's Greenbul supposedly lies. As the rice farmers clear more land for rice, they increasingly see the birds who eat the rice as pests. It is reported that poison is even being used in some areas. Sassi's Greenbul might be negatively impacted by this practice (Odull et al., 2010).

This species seems to be a specialist that has difficulty adapting to secondary environments.

The degree to which the bird's habitat is protected is questionable due to lack of data (Birds of the World).

There is so much unknown about the Sassi's Greenbul's range and habitat. All that is known about the bird is based off of observations made at the sites where specimens of the species were collected. Sassi's Greenbul could be located in yet unexplored areas within the Democratic Republic of the Congo or in neighboring countries. This is the opinion of the Congolese government's Information Office, "Within the vast expanse of the country [Congo], there exists numerous regions that have not yet been explored from an ornithological perspective. [This applies] as much to the heart of equatorial forests as it does outside of them" (Translated from French by Nick Ortiz).

The habitat loss seen across Sassi's Greenbul's range is also the result of the indirect and direct impacts continuous armed conflict has had on diverse ecosystems in the DR Congo. During a wartime situation, there are several ways an armed conflict can negatively affect wildlife. Animals can be accidentally killed by mines or shells. They can be hunted and overexploited to feed troops. If they are an endangered species, they can even be used by hostages or pawns to hamper government troops or gain international support. War can affect park institutions in a reserve where endangered and vulnerable species are protected. Rebels can occupy an area and chase park officials away. With park institutions absent, this not only opens the door for rebels and poachers but also refugees from neighboring regions affected by the conflict to come in and overexploit park resources and destroy natural environments (Gaynor et al., 2016). All of these factors either have happened or continue to happen on some level in the DR Congo ever since the country ceased to be a Belgian colony in the 1960s. The armed conflict that has ravaged the country does not show signs of ending anytime soon. While large mammals tend to be the center of attention for economic reasons such as poaching, birds can be the target of poaching and habitat loss as war forces many in the country to overexploit resources to survive.

The DR Congo has among the richest and diverse ecosystems in the world. Ironically, these areas are also among the most poorly studied and ravaged by habitat loss as a result of the incessant warfare that has plagued the country since independence. Sassi’s Greenbul is one of 13 rare species that are either only known from the DR Congo or are mainly known from this region. Other than Sassi’s Greenbul, the list includes the Itombwe Nightjar, Itombwe Owl, Chestnut Owlet, Grauer’s Cuckooshrike, Lendu Crombec, Kabobo Apalis, Prigogine’s Greenbul, Chapin’s Mountain Babbler, Prigogine’s Sunbird, Upemba Masked Weaver, Black-Lored Waxbill, and Yellow-Legged Weaver. It appears that more and more of their habitat is destroyed by agriculture and overexploitation and more and more of their members are captured or killed due to poaching and hunting with every passing year. If the armed conflict in the DR Congo does not cease, it is unsure how much longer these rare species can continue to cope with the direct and indirect impacts war has had on their survival. 

Sassi's Greenbul is very similar in appearance to the Icterine Greenbul. Below is a comparison to help with identification:

Crown Patch- Sassi's Greenbul- unique black crown path, Icterine Greenbul- none

Overall Appearance- Sassi's Greenbul- darker overall with green underparts (especially on the throat and belly) and is more olive-green throughout with some ginger and a rufous tint on the tail, Icterine Greenbul- brighter overall with yellow underparts, paler, contrast between the rufous upper-tail coverts and rump and an olive-green back

Eye- Sassi's Greenbul- brown, Icterine Greenbul- paler, greyish or grey-brown

Bill (male/female)- Sassi's Greenbul- 15.55/14.28, Icterine Greenbul- 15.34/14.01

Tarsus (male/female)- Sassi's Greenbul- 18.47/17.99, Icterine Greenbul- 18.25/17.73

Wing (male/female)- Sassi's Greenbul- 74.63/69.92, Icterine Greenbul- 74.87/68.47

Tail (male/female)- Sassi's Greenbul- 68.93/63.24, Icterine Greenbul- 70.25/63.62 (Fishpool, 2006)

Research the range overlap between Sassi's Greenbul and the Icterine Greenbul. It is possible that Sassi's Greenbul can be seen in the same areas as the Icterine Greenbul despite claims of the species being restricted to certain locales.

Push for a DNA analysis of all Sassi's Greenbul specimens to see if Sassi's Greenbul and the Icterine Greenbul are indeed the same species. If they are, Sassi's Greenbul can be included within a broader, comprehensive conservation approach geared towards the Icterine Greenbul's range. Right now, many conservationists are considering the same for the Liberian Greenbul based on recent DNA evidence that suggests this bird is an Icterine Greenbul. While a DNA analysis may not completely dispel any doubt over the status of Sassi's Greenbul (only finding the bird and more field research can do that), it can certainly shed some light into this bird's origins and identity.

If possible, encourage birdwatchers and birders living in areas close to the Sassi's Greenbul's range to keep their eyes open and report any sightings to eBird, especially in Apharama in the Okapi Reserve in the Democratic Republic of the Congo where the last confirmed sighting occurred in 1996. It is possible that someone may have already seen the bird and has simply not reported their sighting.

It has been suggested by some that Sassi's Greenbul is not a distinct species but is actually a melanic morph of the Icterine Greenbul. They point towards the study done by Lincoln Fishpool (2006) who analyzed 40 of the 44 specimens of Sassi's Greenbul that were sent to museums since the bird was first described in 1914. His conclusion was he could not find any characteristics that were distinguishing enough to convince him that the two are the different species. He argues that, while the black crown of the Sassi's Greenbul specimens vary in terms of their black crown, this phenomenon is not uncommon among Icterine Greenbuls. He also notes that the two species are similar in size and only differ in the degree of melanin in their plumage and irides. In terms of sex, he finds, "no statistically significant morphometric differences between them."

Furthermore, he contends that the range of the Icterine Greenbul encompasses that of Sassi's Greenbul. While Sassi's Greenbul is said to inhabit transition and lower montane forest zones at a higher altitude (1,820 m) (much higher than the Icterine Greenbul at 1,580 m), he puts forward the argument that errors could have made in terms of measurements and descriptions since many of the Sassi's Greenbul specimens were not collected by the ornithologists themselves who described them. If he is correct, this increases the chance of range overlap between the two species. In terms of behavior, Fishpool argues that both species gather in small groups in lower and middle strata and often join mixed-species flocks. With regards to where the Sassi's Greenbul specimens were found, he lists the inconsistencies regarding certain sites (such as Lake Kivu, Itombue, and the forests west of Lake Edward). It is possible that Sassi's Greenbul is not found in these areas at all.

Are the Sassi's Greenbul and the Icterine Greenbul the same species? Fishpool concludes that that Sassi's Greenbul is likely a melanic morph of the Icterine Greenbul. He speculates that the Sassi's Greenbul's characteristic black crown is the result of an acromelanism where the cooler parts of the bird's body are more pigmented than the warmer parts. This may be due to the temperature of the environment Sassi's Greenbul is said to inhabit. This can also apply to the Sassi's Greenbul's dark eye color. While Fishpool admits that one cannot know for sure without more field research and DNA analysis, he is bold in his assertion that Sassi's Greenbul is not a true species, "I suggest that sufficient evidence is available to cast serious doubt on the specific status of Sassi's Olive Greenbul...such a change of status potentially has practical implications" (Fishpool, 2006).

In 2017, a DNA analysis was done on the lone specimen of the elusive Liberian Greenbul that was collected in 1984. The scientists concluded that this bird was not a distinct species. In fact, it turned out to be a juvenile Icterine Greenbul that had a nutritional deficiency which affected the bird's plumage. They also added the caveat that testing was done only on one specimen claiming to be a Liberian Greenbul and that more research into whether or not this is a distinct species or not depends on whether more members of this species can be found (Science Alert).

Could Sassi's Greenbul be an Icterine Greenbul with a melanism, nutritional deficiency, or plumage variation that depends on their environment? The debate over the Sassi's Greenbul's status as a species will probably continue to rage until either more members of this species are found and studied or a DNA analysis is done on one or more of the specimens that now lie in museums.

Order: Passeriformes

Family: Pycnonotidae

Genus: Phyllastrephus

Species: Phyllastrephus lorenzi

Sassi's Greenbul was previously considered a subspecies of the Icterine Greenbul (Phyllastrephus icterinus) (IUCN Red List)