Demography and Populations

The population biology of the Mrs. Moreau's Warbler is poorly known, with no information on nest success, longevity, survivorship, or population regulation. No formal surveys to quantify abundance have been undertaken and only qualitative population estimates have been made. It is patchily distributed within its range, but can be locally fairly common in the Uluguru Mountains (23 Stuart, S. N., and F. P. Jensen (1985). The avifauna of the Uluguru Mountains, Tanzania. Gerfaut 75:155–197. Close , 24 Svendsen, J. O., and L. A. Hansen (Editors) (1995). Report on the Uluguru Biodiversity Survey 1993. Part A. Royal Society for the Protection of Birds & Tanzania Forestry Research Institute & Centre for Tropical Biodiversity, Sandy, United Kingdom. Close ), and locally common to moderately frequent in the Ukaguru Mountains (26 Stuart, S. N., and T. A. van der Willigen (1978). Report of the Cambridge Ecological Expedition to Tanzania 1978. Cambridge, United Kingdom. Unpublished report. Close , 27 Evans, T. D., and G. Q. A. Anderson (1993). Results of an ornithological survey in the Ukaguru and East Usambara mountains, Tanzania. Scopus 17:40–47. Close ). In the Rubeho Mountains, it seems to be very local, and is so far only recorded from near the eastern ridge of Ukwiva Forest (5 Bowie, R. C. K., J. Fjeldså, and J. Kiure (2009). Multilocus molecular DNA variation in Winifred’s Warbler Scepomycter winifredae suggests cryptic speciation and the existence of a threatened species in the Rubeho–Ukaguru Mountains of Tanzania. Ibis 151:709–719. Close ). BirdLife International has estimated the total population at 500‒1,500 individuals (see Population Status).

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Individual Distance

Information needed.

Territory Size

Information needed. In the Uluguru Mountains, in areas with high density of pairs there were generally 200‒300 m between territory centers (24 Svendsen, J. O., and L. A. Hansen (Editors) (1995). Report on the Uluguru Biodiversity Survey 1993. Part A. Royal Society for the Protection of Birds & Tanzania Forestry Research Institute & Centre for Tropical Biodiversity, Sandy, United Kingdom. Close ).

Home Range Size

Information needed.

Numbers

Information needed. No survey data are available to generate quantitative estimates of density and population size.

In the Uluguru Mountains, reported to be locally fairly common based on fieldwork in 1993 (24 Svendsen, J. O., and L. A. Hansen (Editors) (1995). Report on the Uluguru Biodiversity Survey 1993. Part A. Royal Society for the Protection of Birds & Tanzania Forestry Research Institute & Centre for Tropical Biodiversity, Sandy, United Kingdom. Close ). Since this mountain range holds ca. 120 km² of montane forest (N. Burgess in litt. 2007, 2012 in 34 BirdLife International (2022) Species factsheet: Scepomycter winifredae. Close ) it likely supports the largest population of this species.

In the Ukaguru Mountains, it is known only from Mamiwa-Kisara North Forest Reserve (8,203 ha) (35 Gwegime, J., M. Mwangoka, E. Mulungu, J. Latham, R. E. Gereau, and N. Doggart (2014). The biodiversity and forest condition of Mamiwa-Kisara North Forest Reserve. TFCG Technical Paper 41. Tanzania Forest Conservation Group, Dar es Salaam, Tanzania. Close ), where most of the fieldwork in these mountains has occurred. There are no population estimates for the Ukaguru Mountains, but the species was found to be moderately frequent at the forest reserve in the early 1990s (27 Evans, T. D., and G. Q. A. Anderson (1993). Results of an ornithological survey in the Ukaguru and East Usambara mountains, Tanzania. Scopus 17:40–47. Close ). However, the amount of habitat within the species' altitude range is limited at Mamiwa-Kisara North Forest Reserve (35 Gwegime, J., M. Mwangoka, E. Mulungu, J. Latham, R. E. Gereau, and N. Doggart (2014). The biodiversity and forest condition of Mamiwa-Kisara North Forest Reserve. TFCG Technical Paper 41. Tanzania Forest Conservation Group, Dar es Salaam, Tanzania. Close ), so the population there is presumed to be small.

In the Rubeho Mountains, it has only been recorded from the humid eastern edge of Ukwiva Forest Reserve (54,635 ha), while surveys in Mafwemiro and Mangalisa forests did not detect the species (5 Bowie, R. C. K., J. Fjeldså, and J. Kiure (2009). Multilocus molecular DNA variation in Winifred’s Warbler Scepomycter winifredae suggests cryptic speciation and the existence of a threatened species in the Rubeho–Ukaguru Mountains of Tanzania. Ibis 151:709–719. Close ). The Ukwiva population could number anywhere from a few hundred to a few thousand mature individuals (5 Bowie, R. C. K., J. Fjeldså, and J. Kiure (2009). Multilocus molecular DNA variation in Winifred’s Warbler Scepomycter winifredae suggests cryptic speciation and the existence of a threatened species in the Rubeho–Ukaguru Mountains of Tanzania. Ibis 151:709–719. Close ).

BirdLife International estimated the total population at 500–1,500 individuals based on an estimate by L. Hansen (L. Hansen in litt. 2016 in 34 BirdLife International (2022) Species factsheet: Scepomycter winifredae. Close ) which roughly equates to 330–1,000 mature individuals (34 BirdLife International (2022) Species factsheet: Scepomycter winifredae. Close ). This estimate seems low since the number of individuals in Rubeho alone was believed to be at least a few hundred (5 Bowie, R. C. K., J. Fjeldså, and J. Kiure (2009). Multilocus molecular DNA variation in Winifred’s Warbler Scepomycter winifredae suggests cryptic speciation and the existence of a threatened species in the Rubeho–Ukaguru Mountains of Tanzania. Ibis 151:709–719. Close ).

Trends

No quantitative estimates are available, but the population is believed to be experiencing a decline due to ongoing habitat loss and degradation.

Information needed.