David J. Pearson

Passerine migration strategies and body mass variation along geographic sectors across East Africa, the Middle East and the Arabian Peninsula

Using the body mass estimates of 12 long-distance migrating Palearctic passerine species monitored at successive sites across the Eastern Africa flyway, we tested whether birds modulate their body mass according to specific seasonal demands across different geographic sectors. We compared body mass estimates across latitudinal distances and geographic sectors in Europe, the desert, Northeast Africa and East Africa. Our results show that, depending on the species and season considered, the average body mass increase or decrease is variable at and among different geographic sectors. By comparing the variation in body mass between different ecological sectors, we were able to show when and where migrants accumulate their migratory fuel reserves during migration.

The seasonal separation of primary and secondary moult in Palaearctic passerine migrants on the Sudan coast

In six Palaearctic passerine species caught in autumn on the Sudan Red Sea coast, adults with fully moulted primaries still retained most or all of their old secondaries. This seasonal split of the moult of the two flight feather tracts is discussed, and the strategy is compared with more typical moult suspension.

Biometrics, moult and migration of Grey Plovers, Pluvialis squatarola, at Mida Creek, Kenya

Ringing data for 269 Grey Plovers, Pluvialis squatarola, caught between 1977 and 1988 were analysed. Adults started primary moult soon after arrival in August and September. Mean starting date of adult primary moult was estimated to be 13 September, primary moult duration as 130 days. First-year birds had not started primary moult by early May. Body mass of adults in primary moult was stable from September to February, averaging 205 g, but increased at the end of the moult in March and April. Pre-migratory body mass was estimated at 268 g and would allow a non-stop flight as far as the southeastern Mediterranean or the northern Persian Gulf. Mean wing length increased in March and April, possibly due to the arrival of longer-winged migrants from southern Africa or an earlier departure of males. A decrease in numbers was observed from the second half of April and by mid-May all adults had left the area. In June/July, the number of first-year birds was c. 25% of the total summer population.

An isolated population of Singing Cisticola, Cisticola cantans, in Angola

The Singing Cisticola Cisticola cantans is widely distributed from Mali and most of West Africa east to Ethiopia, south on the east to Zimbabwe and Mozambique. The distribution is curiously patchy in places, with isolated populations in Chad and Sudan, in the Democratic Republic of Congo (DRC) and on the border between Zimbabwe and Mozambique (Tye 1997). Although a population is shown to be present in south-central DRC and on the border between DRC and north-eastern Angola, it is not specifically mentioned by Tye (1997), and was apparently unknown to Lynes (1930) in his review of the genus. There is also one specimen (RMCA 86905) in the Royal Museum for Central Africa, Tervuren, Belgium, from Shaba (Katanga), collected by Allard on 25 May 1957 at Le Marinel (10°20’S, 25°25’E, derived altitude 1 230m) on the Lualaba River northwest of Kolwezi (M Herremans pers. comm.). It is of interest to report the existence of one or possibly two apparently isolated populations of Cisticola cantans in the north-eastern and central Angolan highlands. Five specimens, provisionally identified as C. cantans, were collected by Gerd Heinrich in Angola in 1958. These were not listed by Ripley and Heinrich (1960, 1966) or by Ripley and Bond (1979), but were provisionally included in the Angolan list by Dean (2000). Details of the specimens are: (1) an adult female collected 60km north of Sombo, Lunda Sul (08°44’S, 20°59’E) at 1 100m on 10 March 1958, (2) an adult female collected at Quipeio, Huambo (12°26’S, 15°31’E) at 1 900m on 29 May 1958, (3) a juvenile male collected at Quipeio on 29 May 1958, and two unsexed juveniles collected on the same date at the same locality. The specimens were initially deposited in the Peabody Natural History Museum at Yale University, New Haven, USA, but subsequently three specimens were transferred to the National Museum of Natural History, Washington DC, USA. All five specimens were examined independently by MPSI and DJP, and both have confirmed that the identification is correct. Cisticola cantans was not encountered by Lynes on two extended collecting trips through southern Shaba, Lunda Sul and Huambo (Lynes and Sclater 1934, Lynes 1938) although he collected at Bailundo, less than 50km northeast of Quipeio. This suggests that the Angolan populations are small and probably restricted to particular habitats at high altitudes. Furthermore, Sombo is approximately 600km northeast of Quipeio, suggesting that the Angolan populations are isolated from one another. The species has often been overlooked or confused with the Red-faced Cisticola, C. erythrops; morphologically the two species are, in some forms, very similar, though their voices are distinctive. For example, C. cantans has been found in northeast Zambia, near Mbala (locality not mapped by Tye 1997) (Dowsett-Lemaire and Dowsett 1978), in a well-known area, and it is thus not surprising that C. cantans should have been overlooked in Shaba and northeastern Angola. Cisticola erythrops lepe, which has sometimes been considered a good species (Dowsett and Prigogine 1974), overlaps the range of C. erythrops sylvia and the range of C. cantans belli in southeast DRC, and this may also lead to confusion between the taxa.

Moulting and Wintering Grounds of Marsh Warblers Acrocephalus palustris : Evidence from Stable Isotopes and Ring Recoveries

Abstract. We analysed stable carbon (&dgr;13C) and nitrogen (&dgr;15N) isotope ratios in Marsh Warbler Acrocephalus palustris feathers sampled in Europe and Africa to assess non-breeding habitat selection and location of wintering grounds of different breeding populations. Feather &dgr;13C values showed that Marsh Warblers occupy a biome dominated by C4 vegetation during the stopover in northeastern Africa, whereas C3 habitats are used during the complete moult in southern Africa. East European Marsh Warblers differed in their stable isotope profiles from other European regions, suggesting a certain level of population segregation in southern Africa. A dual-isotope assignment approach confirmed this difference and helped us restrict the autumn staging areas to lower elevations of the Ethiopian Highlands west of the Rift valley. Available ring recoveries, however, suggested high levels of population mixing both on migration through East Africa and in the final wintering grounds.

Towards a better understanding of Basra Reed Warbler Acrocephalus griseldis (Aves: Passeriformes: Acrocephalidae) ecology? A comment on Al-Sheikhly et al. (2013)

Introduction The paper by Al-Sheikhly et al. (2013) described many novel observations that aimed to expand our understanding of the biology of the Basra Reed Warbler Acrocephalus griseldis, a poorly known species of considerable conservation concern (it being currently treated as Endangered by IUCN). However, we believe that significant problems concerning the methodology underlying the data stated to have been collected severely compromise the stated importance of their work, and must raise considerable doubts with respect to at least some of their conclusions.

Rejoinder to the Response of Al-Sheikhly et al.

These remarks are prepared in reply to the Response by Al-Sheikhly et al. to our Comment to Zoology in the Middle East questioning a number of assertions made in their paper: Al-Sheikhly et al. acknowledge that, at best, guesswork was involved in their population estimates, despite no such admission in their original paper. With respect to one of our central concerns, namely their claim of polygyny in Basra Reed Warblers, these authors now admit that “Nevertheless, taking into account the qualitative comments and the literature records provided in Porter et al. (2014), we ... conclude that the occurrence of polygyny in the Basra Reed Warbler needs to be confirmed by a more comprehensive study.” Nevertheless, Al-Sheikhly et al. persist in claiming that they could differentiate males and females in the field, without the aid of in-hand examination and colour ringing, stating merely that “the identification of male and female Basra Reed Warblers was unmistakable in the field”, yet offering no evidence of how this was achieved. As no Acrocephalus species is known to be sexually dimorphic, except in some species in biometrics (Kennerley & Pearson, 2010), which requires handling, this claim lacks any credibility, unless the authors observed numerous acts of copulation and possessed some means of identifying individuals in the field to prove that each of the 317 males (p. 110) consorted with multiple females. If the precise totals originally presented to support the claim of polygyny lack credibility, then it draws into question any of the paper’s other results.