The Griffon Vulture “Luka” is the first bird in a satellite telemetry program from a colony on the Trešnjica River!
Luka is a young male who hatched in the spring of 2019 in the northernmost colony of Griffon Vultures in Europe, the “Trešnjica River Gorge” Special Nature Reserve. He was found extinct near the Drina on the 27.10.2019. years. He was recovered and when the conditions for returning to the colony on Trešnjica were met, we tried to release him on the 7.3.2020. but on that rainy day, Luke did not want to take off.

However, on the 20.03.2020. Luka was again released near the Trešnjica feeding station and this time he took off. Now he is in the monitoring program and within the project of the Birds of Prey Protection Foundation: “Management of the Griffon Vultures Population (Gyps fulvus) in the Special Nature Reserves: “Trešnjica River Gorge” and “Uvac”, at the Ministry of the Environment’s 2019 competition to award funding to support civil society projects in the environmental field.

Here is his move 10 days after its release:

Predrag Bata Ristanovic is one of the founders of the Birds of Prey Foundation and its longtime president. You can read about him:

Kreativna Zaostavština

Sorry, this entry is only available in српски.

Sorry, this entry is only available in српски.

Sorry, this entry is only available in српски.

Griffon Vulture Igor is one of the vultures who has been in the satellite tracking program for some time. Igor was released on 7.9.2019. with satellite transmitter (more about that here… »). He fit in well, often staying at the restorant for vultures, as recorded by video surveillance cameras.

Igor’s Home Range from 7.9-21.11.2019.

20.11. he also visited Mileševka, where the “Emergency” situation happened. According to the data we follow daily, we have noticed that on the 20.11. between 6 and 8 in the morning something significant happened to the transmitter. Most likely the teflon strap was broken. The “xyz axes” of the accelerometer changed abruptly, which clearly indicated that the position of the device, which was on the back of the bird, had suddenly changed and was hanging. Another parameter confirming this change is the sudden drop in temperature registered by the transmitter to just 10C. When the transmitter is on the bird and the condition is regularly the temperature it shows is 20-36C. However, we also knew that the transmitter did not go down and that Igor was moving, surprisingly, very well. He flew over Uvac and behaved normally for the next 28 hours.

Igor’s flight over Uvac
 

We closely followed the events and on the 21.11. at 12 o’clock, the transmitter stopped moving, the temperature was practically ambient (from -2 to 15C, depending on the time of day). The “xyz axes” of the accelerometer indicated that the transmitter was partially facing the ground. Sunlight was well received by the solar panel, and the batteries were charging normally, again indicating that the device was not in too dense vegetation. As there was a possibility that the bird had fallen too, we immediately alerted the Rangers of JP “Reserve Uvac” and sent them the coordinates.

We had the coordinates, but also the difficulty that the transmitter was partially turned to the ground, so GPS “saw” fewer satellites, which meant less location accuracy. The Rangers soon took to the field and were unable to find either the bird or the transmitter.
 
In order to minimize the location error and try to get the Rangers as accurate as possible to the location where the transmitter is located, we have done so-called. “burst”, that is, taking a large number of GPS points and short time. We eliminated all points that were located with fewer satellites and where HDOP (Horizontal Dilution of Precision) was inappropriate. The rest points were the most reliable.

Soon the Ranger team took to the field again, this time with more precise data and found the transmitter!

Many thanks to our Rangers for their quick action and sacrifice!

It remains for us to study the Teflon strap by which the transmitter binds to the bird and to try to determine what exactly happened, or why the transmitter fell. Igor is probably fine and we are awaiting his next finding at the “restourant” or otherwise.

Igor in flight (photo. Violeta Milutinović, work from the competition of the Birds of Prey Foundation Protection “Birds in Action” in 2019)

Frames from the action of finding the transmitter:

On October 27, 2019, the Griffon Vulture named “Luka” fell near the Drina River and “requested” people’s help. Laza, a guard from the Trešnjica River Gorge Special Nature Reserve, transferred him to a cage. Luka was named as a memory of our friend and legend of Tresnjica Luka, a man who made it possible to open and operate a feeding facility on Tresnjica at a time when there was no one else.

This is the third marked Griffon Vulture on Trešnjica, and more recently the first! In 1990, the adult Griffon Vulture named Marko was marked, with a yellow stamp and a no. “1” in collaboration with colleague Ištvan Ham. Marko nested on the Orlovača rock for the next three years and then disappeared. Then, on the Trešnica, the Griffon Vulture Mitar was marked in 1996. We later recorded him only on Uvac, so we estimate that the bird was originally from Uvac and that he got sick while visiting Trešnjica. And there is the El Greco Vulture marked in Greece at the Dadia Reserve in 2002. This bird has been nesting in Trešnjica, on the Vratnica rock from 2008. until today.

However, in recent years we have not had any marked Vultures on Trešnjica and that is why Luka is very important to us. We are working to improve the monitoring of Vultures in Trešnjica. In addition to marking, we also intend to set up a satellite transmitter to get to know about the needs and habits of Griffon Vultures from Trešnjica and to apply effective protection measures to this colony.