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Robust abundance estimates of wild animal populations are needed to inform management policies and are often obtained through mark–recapture (MR) studies. Visual methods are commonly used, which limits data collection to daylight hours and good weather conditions. Passive acoustic monitoring offers an alternative, particularly if acoustic cues are naturally produced and individually distinctive. Here we investigate the potential of using individually distinctive signature whistles in a MR framework and evaluate different components of study design.

Knowledge of a population’s abundance is of primary importance for conservation management. However, robust estimates of abundance are often difficult to obtain, especially for cetaceans which spend most of their lives submerged. Cetacean abundance is commonly estimated using aerial or vessel-based line transect surveys and distance sampling methods. During 2012–2014, the first line transect surveys to estimate cetacean abundance were conducted in Namibian waters.

Knowledge of the occurrence and distribution of cetaceans is particularly important for conservation and management, but is still limited within Namibian waters. We collated 3211 cetacean records from the Namibian Exclusive Economic Zone (EEZ) for the period 2008 to 2016 and applied the principle of minimum cross entropy (MinxEnt) to predict habitat suitability. MinxEnt is a generalised form of maximum entropy modelling that allows incorporation of additional information such as sampling bias.

The coastal population of common bottlenose dolphins Tursiops truncatus found in Namibia is regionally isolated and unique. This population faces several potential anthropogenic threats, especially in Walvis Bay, including boat-based tourism, a commercial harbour undergoing expansion, and aquaculture for oysters and mussels. Between 2008 and 2012, 238 boat-based surveys were conducted, resulting in 170 encounters with bottlenose dolphins. Overall, group sizes varied from 1 to 45 individuals (mean 10.7).

A total of 250,786 Cape Cormorants, of which 16,038 were individuals on nests in 349 colonies, and 15,831 Cape Fur Seals were counted during a complete aerial photographic census of the island of Tigres and part of the adjacent coast in Angola in March 2017. Such a concentration of birds and seals and the large number of breeding Cape Cormorants highlights the need to protect Tigres and its rich surrounding waters. Keywords: aerial census, Arctocephalus pusillus pusillus, Baía dos Tigres, Cape cormorant, Cape fur seal, Phalacrocorax capensis.

Vultures provide essential ecological services, yet are amongst the world's most threatened species with populations having declined by more than 95% within ten years in some places. The biggest factor causing this decline is the use of poison, either intentionally or unintentionally. Other factors causing declines are collision with and electrocution by powerlines, illegal harvesting for traditional medicines, habitat loss and drowning in reservoirs.

The species accounts are very detailed, doubtlessly benefitting from Peter's intimate and long-term knowledge of Botswana's birds. The range maps give one an immediate indication of where the bird occurs and the breeding bars give one an idea of when to expect the bird and when it breeds. These will prove handy when identifying e.g. migratory birds. The excellent illustrations show the birds in their local race and where sexes and ages differ, these are also illustrated. Perhaps one shortcoming of the illustrations is, that diagnostic features e.g.

Summary of the 2015 Summer Wetland Bird Counts in Namibia.

Many long-distance migrating shorebird (i.e., sandpipers, plovers, flamingos, oystercatchers) populations are declining. Although regular shorebird monitoring programs exist worldwide, most estimates of shorebird population trends and sizes are poor or nonexistent. We built a state-space model to estimate shorebird population trends. Compared with more commonly used methods of trend estimation, state-space models are more mechanistic, allow for the separation of observation and state process, and can easily accommodate multivariate time series and nonlinear trends.

The following is a summary of waterbird count data for selected species in Namibia, covering the period 1977 to December 2008.

This is the last article in a series describing the results of regular wetland bird counts in Namibia. This paper looks at eight coastal sites, including two of Namibia's four Ramsar sites i.e. Sandwich Harbour and Walvis Bay. Unfortunately data for Namibia's other coastal Ramsar site, the Orange River Mouth, is incomplete and hence it has not been included in this analysis. (Larger scale replications of the graphs in this article are attached to the end of this edition).

The southern African Lesser Flamingo population was estimated to number 55,000 - 65,000 individuals in the mid-1990s, but these were either under estimates or the numbers have increased since, because at times Kamfers Dam, the Goldfields wetlands (in South Africa), Etosha Pan (Namibia) and Sua Pan (Botswana) each support more than that number. In order to try and get to grips with the size of the southern African population of Lesser Flamingos, a coordinated survey was planned for 20-21 July 2008.

The 30 June 2008 signaled the end of the 2007 ringing season and the following is a summary thereof. In total 9 637 birds of 270 species were ringed or re-trapped, controlled etc. this season. Out of this total 9 033 were newly ringed birds (i.e. SAFRING code 1). Data from 19 ringers was received and Dirk Heinrich once again is the "ringing king" of code 1 birds, followed by Tim Osborne and Mark Boorman but in the re-trap etc. category Tim pipped Dirk, followed by Ursula Franke. Dirk also held top spot in the number of different species ringed category.

Elephants occur across the entire north of Namibia with two main sub-populations in the north-east and the north-west. In 2004 the total population was estimated at over 16,000 animals and, allowing for underestimates on aerial surveys, the true number in 2007 is likely to be closer to 20,000. The north-western population is about 4,000 animals and includes the elephants in Etosha. This appears to be growing at about 3.3% per annum and expanding its range.

This study has provided baseline data on crocodile numbers from aerial and spotlight counts. These data can be used with the results of future counts to determine population trends. The census has also provided information on their distribution of crocodiles in the Kavango and Caprivi regions. And third, it has resulted in the first population estimate for crocodiles in the north-east wetlands of Namibia.

An assessment of population size is a fundamental stage in the conservation of any species. The recent availability of data from the Southern African Bird Atlas Project (SABAP) provides a tool to investigate the status and distribution of approximately 900 bird species covered by this work. Here, we assess whether or not reporting rate can be used to establish absolute abundance and thereby produce estimates of population size.

Short paper discussing previous documented records and interpretation in relation to records data.

Distribution is restricted by the availability of Sociable Weaver nests, rather than by other environmental factors. There is a 26% occupancy rate and the falcons choose larger Sociable Weaver nest masses.