Exposing the secret via satellite
Slowly the four wheel drive vehicle finds its way along the edge of Etosha's Fischer's Pan. Time and again the vehicle from the Ministry of Environment and Tourism has to be reversed when the wheels start sinking into the light grey mud. In the dense grass cover next to the water, holes dug by springhare are difficult to avoid and together with the contours of the edge of the pan make it impossible for a smooth and steady ride. Two days earlier, members of the Crane Working Group of Namibia which includes officials of the Ministry of Environment and Tourism were forced to cover some distance on the southern edge of Fischer's Pan with speed, after being charged by a black rhino bull, which was on its way to the water. When the puffing and angry ton of muscles had disappeared into the bushes, a Blue Crane (Anthropoides paradiseus) that was on the waters edge had also disappeared. This is what the group with driver and researcher Holger Kolberg are looking for.The day before, the members of the Crane Working Group together with Holger Kolberg from the Directorate Scientific Services of the Ministry of Environment and Tourism, were able to drive and fly the area around the pans in the Etosha National Park as well as some of the area south of Lake Oponono in the Oshana region north of the park. During a flight with the Ministry's Cessna 182 piloted by Frans Henning, an adult crane with a chick was spotted next to open water just north of Fischer's Pan. Photographs of the adult and chick taken from the air later revealed that the second adult and another chick had been standing in the high grass only a few meters away from those spotted.
Suddenly a member of the group spots two Blue Cranes at a distance, on the edge of the open grassland. All binoculars are now trained at the cranes and soon two chicks are also discernible in the yellow grass. The vehicle heads straight towards the grey blue birds, which slowly, but steadily move off. Soon the chicks are not seen in the tall grass anymore, the adults only visible when their long necks and heads stick out of the vegetation. A stretch of open water forces the vehicle to make a turn and the adult cranes emerge only a hundred meters away, but there is no sign of the chicks. The adult pair part, both birds take off, flying only meters above the grass plain and land a short distance away.
The members of the Crane Working Group stop under a tree and a short discussion follows as to whether to go and search for the chicks or to wait. Had they remained close to where the adults were first spotted? Or had they followed the adults a short way in the long grass and then ducked down to wait out the chase? Or were they in the close vicinity of their parents?
The adults take to the air again covering a further hundred meters and then land, calling. Everybody searches the area and suddenly, only 20 meters away, a chick gets up. A member of the group rushes towards the young bird, but it ducks down again and is difficult to spot in the dense yellow grass. Eventually the chick is found, captured and carried back to the vehicle. Here it is ringed. A numbered metal ring is fixed on the left leg below the knee and a green plastic ring with an engraved alpha-numeric code is fixed above the knee on the right leg. After being measured and weighed the young Blue Crane is released. The second chick is not spotted and the group decides to leave the area to allow the chicks to rejoin their parents. Late that afternoon the crane family is spotted again, feeding together.
Another pair with two chicks was seen on the edge of the Etosha pan near the turn-off to Chudob waterhole, but when Wilferd Versfeld from the Etosha Ecological Institute in Okaukuejo approached the crane family in his vehicle, the adults with their chicks headed straight towards the water. It was decided, to rather drive down to the water at a distance from the crane family, a day later, and then move in closer. The plan worked, by the time the cranes noticed the vehicle, they were too far from the water's edge. Apparently in no hurry, they walked away from the vehicle which steadily closed in. The cranes and creeping vehicle moved between herds of springbok, oryx, blue wildebeest and Burchell's zebra. When close enough Holger Kolberg and a helper jumped out and off the car and rushed after the differently sized chicks. Both were caught within a short distance with the adults displaying injuries to lure away the perceived predators. Both these chicks were also ringed with the metal and plastic rings. Two more chicks were caught and ringed in the grass plains near Salvadora in the Halali area two days later.
However, the most important task of the members of the Crane Working Group this year was to catch an adult crane and fit a GPS satellite transmitter to the bird. A year earlier an adult Blue Crane was caught and a radio transmitter fitted on the back of the bird. Although the bird was tracked in the park and at Lake Oponono to the north of the park a few times from the ground and air with the help of telemetry equipment, the search for the Blue Crane often delivered no results. During the Crane Working Group's visit to Etosha in April this year, there was, once more, no sign of the crane with the radio transmitter. This lack of success in determining the crane's whereabouts using radio transmitters was the main reason why it was decided to track the Blue Cranes by satellite.
In total darkness, with no moon and only stars in the sky, the group set off in one vehicle to the edge of the pan close to the Namutoni airstrip, where a single Blue Crane had been spotted late that afternoon. First a Grey Heron appeared in the spotlight, standing in the dark water of the pan, then a few nervous waders and then all of a sudden the Blue Crane appeared in the light. Cautiously the excited group moved closer, but the alert crane took to the air. The group watched with bated breath but the bird soon landed again, still caught in the beam of the spotlight. The vehicle approached slowly and this time the big bird stayed in the water, calling softly. One member of the group armed with a torch and a catcher sneaked up to the bird and about half an hour later the bird was caught, ringed and measured. Then the most important task followed; the solar powered GPS satellite transmitter was fitted to a harness on the back of the crane and activated. The transmitter will now record the position of the crane every four hours. Soon thereafter the crane was released, walking away into the darkness. The first information received two days later, revealed that the bird had moved away from the pan to the plains at the turn-off to Chudop and then back to the spot where he was caught in the early hours of the morning. Since then the data received from the transmitter has shown that the crane has moved within Fischer's Pan slowly to the east, covering about 10 kilometres. The researchers and members of the Crane Working Group are delighted with the results so far. Hopefully this bird will reveal some of the secrets of the movements of this small, isolated Blue Crane population in Namibia. A second satellite transmitter could not be fitted, as a second adult crane could not be caught because the birds were just too alert.
During aerial and ground surveys in April 2006, after an above average rainy season, the Crane Working Group counted just over 60 Blue Cranes in Etosha National Park and the area around Lake Oponono to the north of the park. In April 2007, when the rainfall was way below average, just 30 Blue Cranes were spotted during a similar survey. This year during the survey in April, only nine adult birds and six chicks were counted in Etosha and none to the north of the park. However, south of Lake Oponono in the flooded plains of the Oshana region four Grey Crowned Cranes (Balearica regulorum) were spotted from the air, two of which were on a nest. There are no previous records of crowned cranes breeding in Namibia. Both birds were observed lying flat on the nest or next to it with their long necks on the ground when the airplane approached. One single crowned crane was seen together with three Wattled Cranes (Bugeranus carunculatus) and another one was spotted on the edge of an island where presumably its mate was ducking next to the nest. Altogether, 22 Wattled Cranes were counted during the aerial survey.
Very little is known about the three crane species occurring in Namibia. The Namibian Blue Crane population is thought to be about 60 birds only. In South Africa, 20000 Blue Cranes are estimated to occur, which seem to have no contact with the small Namibian group. It might be that the local birds move into southern Angola and hopefully data from the satellite transmitter, which weighs only 40 grams and should be active for at least four years, will give some answers to these questions. The price of one GPS transmitter is US$4000 (N$28000). The cost of the two transmitters was covered by the Polytechnic of Namibia. The requisite downloading and data processing by Argos in France costs another 150 Euros per month which is being covered for one year by the Ramsar Small Grants Fund.
Some of the chicks colour ringed in 2006, were seen in Etosha's Namutoni area at the beginning of last year and towards the end of 2007. This year none of the marked Blue Cranes were seen. Tourists are requested to report any sightings of cranes to the researchers from the Ministry of Environment and Tourism or to the Crane Working Group and to take special note of whether any markings are present. Information can be send to holgerk@mweb.com.na or versfeld@mweb.com.na
Suddenly a member of the group spots two Blue Cranes at a distance, on the edge of the open grassland. All binoculars are now trained at the cranes and soon two chicks are also discernible in the yellow grass. The vehicle heads straight towards the grey blue birds, which slowly, but steadily move off. Soon the chicks are not seen in the tall grass anymore, the adults only visible when their long necks and heads stick out of the vegetation. A stretch of open water forces the vehicle to make a turn and the adult cranes emerge only a hundred meters away, but there is no sign of the chicks. The adult pair part, both birds take off, flying only meters above the grass plain and land a short distance away.
The members of the Crane Working Group stop under a tree and a short discussion follows as to whether to go and search for the chicks or to wait. Had they remained close to where the adults were first spotted? Or had they followed the adults a short way in the long grass and then ducked down to wait out the chase? Or were they in the close vicinity of their parents?
The adults take to the air again covering a further hundred meters and then land, calling. Everybody searches the area and suddenly, only 20 meters away, a chick gets up. A member of the group rushes towards the young bird, but it ducks down again and is difficult to spot in the dense yellow grass. Eventually the chick is found, captured and carried back to the vehicle. Here it is ringed. A numbered metal ring is fixed on the left leg below the knee and a green plastic ring with an engraved alpha-numeric code is fixed above the knee on the right leg. After being measured and weighed the young Blue Crane is released. The second chick is not spotted and the group decides to leave the area to allow the chicks to rejoin their parents. Late that afternoon the crane family is spotted again, feeding together.
Another pair with two chicks was seen on the edge of the Etosha pan near the turn-off to Chudob waterhole, but when Wilferd Versfeld from the Etosha Ecological Institute in Okaukuejo approached the crane family in his vehicle, the adults with their chicks headed straight towards the water. It was decided, to rather drive down to the water at a distance from the crane family, a day later, and then move in closer. The plan worked, by the time the cranes noticed the vehicle, they were too far from the water's edge. Apparently in no hurry, they walked away from the vehicle which steadily closed in. The cranes and creeping vehicle moved between herds of springbok, oryx, blue wildebeest and Burchell's zebra. When close enough Holger Kolberg and a helper jumped out and off the car and rushed after the differently sized chicks. Both were caught within a short distance with the adults displaying injuries to lure away the perceived predators. Both these chicks were also ringed with the metal and plastic rings. Two more chicks were caught and ringed in the grass plains near Salvadora in the Halali area two days later.
However, the most important task of the members of the Crane Working Group this year was to catch an adult crane and fit a GPS satellite transmitter to the bird. A year earlier an adult Blue Crane was caught and a radio transmitter fitted on the back of the bird. Although the bird was tracked in the park and at Lake Oponono to the north of the park a few times from the ground and air with the help of telemetry equipment, the search for the Blue Crane often delivered no results. During the Crane Working Group's visit to Etosha in April this year, there was, once more, no sign of the crane with the radio transmitter. This lack of success in determining the crane's whereabouts using radio transmitters was the main reason why it was decided to track the Blue Cranes by satellite.
In total darkness, with no moon and only stars in the sky, the group set off in one vehicle to the edge of the pan close to the Namutoni airstrip, where a single Blue Crane had been spotted late that afternoon. First a Grey Heron appeared in the spotlight, standing in the dark water of the pan, then a few nervous waders and then all of a sudden the Blue Crane appeared in the light. Cautiously the excited group moved closer, but the alert crane took to the air. The group watched with bated breath but the bird soon landed again, still caught in the beam of the spotlight. The vehicle approached slowly and this time the big bird stayed in the water, calling softly. One member of the group armed with a torch and a catcher sneaked up to the bird and about half an hour later the bird was caught, ringed and measured. Then the most important task followed; the solar powered GPS satellite transmitter was fitted to a harness on the back of the crane and activated. The transmitter will now record the position of the crane every four hours. Soon thereafter the crane was released, walking away into the darkness. The first information received two days later, revealed that the bird had moved away from the pan to the plains at the turn-off to Chudop and then back to the spot where he was caught in the early hours of the morning. Since then the data received from the transmitter has shown that the crane has moved within Fischer's Pan slowly to the east, covering about 10 kilometres. The researchers and members of the Crane Working Group are delighted with the results so far. Hopefully this bird will reveal some of the secrets of the movements of this small, isolated Blue Crane population in Namibia. A second satellite transmitter could not be fitted, as a second adult crane could not be caught because the birds were just too alert.
During aerial and ground surveys in April 2006, after an above average rainy season, the Crane Working Group counted just over 60 Blue Cranes in Etosha National Park and the area around Lake Oponono to the north of the park. In April 2007, when the rainfall was way below average, just 30 Blue Cranes were spotted during a similar survey. This year during the survey in April, only nine adult birds and six chicks were counted in Etosha and none to the north of the park. However, south of Lake Oponono in the flooded plains of the Oshana region four Grey Crowned Cranes (Balearica regulorum) were spotted from the air, two of which were on a nest. There are no previous records of crowned cranes breeding in Namibia. Both birds were observed lying flat on the nest or next to it with their long necks on the ground when the airplane approached. One single crowned crane was seen together with three Wattled Cranes (Bugeranus carunculatus) and another one was spotted on the edge of an island where presumably its mate was ducking next to the nest. Altogether, 22 Wattled Cranes were counted during the aerial survey.
Very little is known about the three crane species occurring in Namibia. The Namibian Blue Crane population is thought to be about 60 birds only. In South Africa, 20000 Blue Cranes are estimated to occur, which seem to have no contact with the small Namibian group. It might be that the local birds move into southern Angola and hopefully data from the satellite transmitter, which weighs only 40 grams and should be active for at least four years, will give some answers to these questions. The price of one GPS transmitter is US$4000 (N$28000). The cost of the two transmitters was covered by the Polytechnic of Namibia. The requisite downloading and data processing by Argos in France costs another 150 Euros per month which is being covered for one year by the Ramsar Small Grants Fund.
Some of the chicks colour ringed in 2006, were seen in Etosha's Namutoni area at the beginning of last year and towards the end of 2007. This year none of the marked Blue Cranes were seen. Tourists are requested to report any sightings of cranes to the researchers from the Ministry of Environment and Tourism or to the Crane Working Group and to take special note of whether any markings are present. Information can be send to holgerk@mweb.com.na or versfeld@mweb.com.na
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