by Ann & Mike Scott
With Namibia in the grip of one of the worst droughts on record, provisional rainfall data for the past year/season for Halali amounts to only about 160 mm, and for Okaukuejo 90 mm, compared to a mean of around 400 mm (and maxima of over 600 mm, e.g. in 1953/54, 1975/76 and 2010/11). (No figures are available for Namutoni for the past season at this stage.)
These extreme conditions have taken their toll on the latest Blue Crane breeding season. Most of the breeding sites have dried up considerably (see photos of Charitsaub above, and also of Salvadora on p4).
The proximity of water is essential for the survival of the cranes. NCJ (ringed 2014) and an unringed companion at Nebrownii waterhole in February 2019 (photo Valmik Soni). The availability of water is essential for breeding success, for cooling and for predator evasion. Only three chicks were produced (namely 1 at Twee Palms [27/2/19]; 2 at Chudop [late April]), and none of these have survived.
The Namibia Crane Working Group has conducted a number of ongoing surveys to try and record the rather unpredictable numbers, movements and breeding success of the cranes under these conditions – many thanks to all our dedicated contributors. Our maximum for 2018 now stands at 28; and for 2019 (to date) at 33.
19-25/11/2018: Hanjo Böhme (gmbhanjo@iway.na) & Dirk Heinrich
In order to get a full count for the dry season, a thorough survey was done in November 2018. Etosha was very dry and hot. We counted a total of 27 cranes, to which one more bird could be added (NCN, observed on 18/11/18; see report by R Tempel below), bringing the maximum count for 2018 to 28. We checked Andoni twice (20 & 22/11/18; 21 and 23 Blue Cranes), because we are pretty sure that that is the corridor, where all the cranes come through to reach Etosha before they disperse to different breeding sites inside Etosha. Andoni waterhole was full and thousands of animals congregate there to quench their thirst … I think all the waterholes are under tremendous pressure, because all the animals need water and some of these holes cannot supply anything.
The following 8 ringed birds were seen (five older ringed birds and three younger ones):
• NHF (ringed in 2005 at Chudop) & NHH (2006, east of Salvadora) – our regular pair already at Charitsaub (19/11/18)
• NHD (2005, east of Rietfontein) & NBN (2007, Salvadora) – the Halali Seepage pair, although still at Andoni
• NBZ (2007, Causeway) – reported regularly in Chudop area, seen at Koinachas with an unringed bird (21 & 23/11/18)
• NCJ (2014, Seepage) – has tried to breed at Nebrownii, still at Andoni
• NCK (2014, Salvadora) – tried to breed at Newbrownii in 2016, still at Andoni
• NER (2018, Twee Palms – good to see it has survived), at Andoni
We also visited Ivan Kasozi, the General Manager at Mokuti Etosha Lodge, and handed over a bird field guide (a donation from the Namibia Bird Club) and binoculars for one of the tour guides who is interested in birding. The Lodge kindly provided landing facilities for our aerial survey in August 2018 (see Newsletter No. 57).
9/1/19 Gabriel Shatumbu (gshatumbu@gmail.com), Ann & Mike Scott
A summary of the crane sightings we obtained during a very thorough survey of all the usual sites on 9/1/19 – thanks again to Gabriel for all the help.
– 08h31 Charitsaub: 0
– 08h35 Salvadora: 0
– 09h00 Rietfontein plains: 4 (1 ringed)
– 09h30 Halali plains: 2 (NCK + unringed)
– 09h45 Halali Seep: 2
– 12h00 Chudop triangle: 2 (NBZ + unringed) – 13h50 Andoni: 4 (NCJ + 3 unringed) *Charitsaub or Salvadora both fairly dry TOTAL 14
21/3/19 Gabriel Shatumbu
Andoni = 33 total, 8 with green tags but unable to read
them. No cranes at any of the other sites.
(ED: This is the highest count since 32 in 2017 and 35 in 2011)
18/3/19 Gabriel Shatumbu & Herman Martin (MET)
18.03.2019 (11:30) 11 blue cranes at Andoni waterhole, all adults as per Herman Martin, again he continued: late last month I saw two small chicks with parents at Chudop triangle.
28/3/19-1/4/19 Ann & Mike Scott (ecoserve@iway.na)
It seems that the cranes have left. We spent several days looking everywhere for them, but no sign of any cranes, nor chicks. There were none at Andoni, where we had been hoping to see at least some of the eight ringed birds that Gabes found there with his count of 33 on 21/3/19; this would have been a good representation of all/most of the ringed birds that are around (but also see the count of November 2018 above).
The comparative photos of Charitsaub (p1) and Salvadora (right) give an indication of how dry this season has been.
6-13/4/19 Hanjo Böhme & Ute von Ludwiger
We really tried hard for the whole week to get crane sightings and travelled those known routes twice (Andoni three times) during the course of the week; but no cranes were seen.
12/4/19 Gabriel Shatumbu
21 blue cranes at Andoni area far from waterhole feeding among blue wildebeest; 5 green rings, very far to read.
10/6/19 Herman Martin 11 cranes at Andoni.
PLANS FOR MORE SATELLITE TRACKING
Our key questions remain: what are the reasons for the decline in Blue Crane numbers, where is this happening and how can the causes be addressed?
It is considered that satellite telemetry may still be the best way to reveal the population sink, and that we should continue with our efforts in this regard.
Through our associate Gabriel Shatumbu of the Ministry of Environment and Tourism (MET) at the Etosha Ecological Institute, Dr Paul Howey of Microwave Telemetry (MT) has kindly donated four tags for this purpose: two satellite PTTs and two GSM transmitters. MT has also undertaken to cover the GSM service.
Generous sponsorship (USD 3,000 or N$45,000) for the Argos tracking services for the above two PTTs (including crane capture) has been provided by the Leiden Conservation Foundation Project Fund (Tom and Kathy Leiden), facilitated by Kerryn Morrison of the International Crane Foundation/Endangered Wildlife Trust (ICF/EWT) Partnership. It is envisaged that the trackers could provide data for around three years.
The Max Planck Institute for Ornithology in Germany has also made an invaluable donation of ten Lika Uni KN GPS/GSM tags. This process was kindly facilitated by Ortwin Aschenborn and Martin Wikelski – and Gabriel.
All of the above tags are leg-mounted designs.
The MET will also continue to provide support and co- funding in kind, in the way of staff assistance (time, expertise and travelling), and accommodation for the crane tagging. Holger Kolberg has been testing the satellite tags for us.
We are now in the process of planning a capture with a focus on older birds, probably using a mag-lite at night, provided that the cranes continue to visit the Andoni area.
The full reference is:
Scott A, Scott M, Altwegg R, Böhme H, Brain C, Gariseb S, Guim S, Kapner J, Kolberg H, Mendelsohn J, Shatumbu G, Simmons R, Versfeld W, Vilho A. June 2019.