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Satellite Honey Buzzard ”Lasse”

A breeding Honey Buzzard Pernis apivorus male was equipped with a satellite transmitter in Kokemäki (western Finland) the 9th of August, 2010. He was named “Lasse”. Lasse is the first satellite-tracked Honey Buzzard in Finland. The aim of this project is to follow autumn migration, find out the wintering area and, if the duration of battery will allow it, to follow the spring migration back to Finland. The few Finnish ring recoveries suggest that our Honey Buzzards spend their winter in tropical Africa.

Background

The size of the Finnish Honey Buzzard population is 3,000–4,000 pairs. The species has decreased considerably during the last few years. In Finland, the biggest threat for the Honey Buzzard is intense forestry which destroys breeding sites and increases competition for them with other bird of prey species. During the migration Honey Buzzards are still illegally killed by hunters, especially in the Mediterranean region.

Lasse’s transmitter is a traditional Argos battery-powered model (made by NorthStar). The weight of the unit is 20g. The duty cycle of the transmitter is programmed so that it is 8 hours ON and then 108 hours OFF, which means that locations are obtained on average at 4,5-day intervals. The expected duration of the battery is approximately 550 hours (i.e., 9–10 months).

Accuracy of location data

In maps, the accuracy of locations is shown either with numbers (“accurate”) or with letters (“inaccurate”):

3 = < 150m
2 = < 350m
1 = < 1000m
0, A, B = > 1000m

For clarity, only accurate locations have been shown in Finland, but in abroad all locations are shown. By clicking the dots in the map it is possible to see additional information on location data (date, GMT-time, coordinates, accuracy of location).

Autumn migration 2010

14 August

Lasse was located 2km away from its nest. Lasse’s responsibility was to take care of two offspring who were already able to fly but had not left the nest yet.

19 August

Lasse was surprisingly far away from his nest: first location came 20km southeast from the nest. During the following three hours, when he was obviously returning to the nest, he was still nine kilometres from it.

24 August

There was only one location showing that Lasse was near his nest. The weather forecast predicted that during the next few days the temperature would fall considerably. Possibly Lasse would start his migration soon.

29 August

The long and dangerous autumn migration had started! Lasse was located in southern Lithuania early in the morning.

3 September

Only one inaccurate location from western Ukraine was received.

7 September

No location data were received, most likely due to very high radio disturbance in southeastern Europe. However, the transmitter got through one message telling that the temperature of the unit was +30C. This suggests that the bird was still alive.

12 September

Lasse had reached Calabria, south Italy. During less than three weeks, he had traveled more than 2,500km from his nest. The next few days will be full or dangers because of hunters in Malta and Sicily, flight over the Mediterranean and, finally, the long and exhausting flight across the Sahara desert.

17 September

Five inaccurate locations were received from southwest Libya, approximately 750km from the city of Tripoli. Up to present, Lasse had traveled more than 4,000km at an average daily speed of 170km. However, during the last trip from south Italy the average speed was almost 300km per day!

22 September

Lasse was already in southern Niger, only a few kilometres away from the Nigerian border. During five hours of locations, he was constantly flying towards southeast and traveled 130km during this short time.

27 September

Lasse’s trip had continued deep inside Nigeria. Altogether, six locations were received and four of them were accurate (< 1,000m). Since 22 September, Lasse had proceeded 560km which is clearly less than during the previous two trips (Italy–Libya and Libya–Niger). This may indicate that he is already close to his wintering area.

2 October

Contrary to earlier expectations, Lasse has continued his journey. During the last five days he has traveled 650km southeast and ended up in southern Cameroon. Although there appears to be slight variation between the four locations, Lasse most probably stayed all night near the most accurate location point (number 33 in maps) - the activity sensor of the transmitter indicated that the bird did not move. Up to present, Lasse has flown at least 7,000km from his nest site.

6-7 October

For some reason Lasse was not satisfied with Cameroon: since 2 October he had flown 212 km to southeast and spent the night between 6 and 7 October in northern Gabon. He was probably sleeping all night close to the location point 39 (the other locations are more inaccurate).

Winter 2010-2011

11 October

It seems that Lasse has finally reached his wintering area in northern Gabon: during the last five days he did not continue his journey any more. The autumn migration took approximately 5 weeks and during this time the bird traveled more than 7,200km. During the wintering season, only the most accurate locations are shown on the map.

16 October

Lasse spent all day in the same area in which he arrived around 10 days ago. - From now onwards these texts will be updated only in case something new or exceptional should occur. However, the locations will be updated on the maps regularly at approximately 5-day intervals.

4-5 November

Quite unexpectedly, Lasse had continued his journey between 31 October and 4 November. Now he was located roosting in Central Gabon, just south of the Lopé National Park. This new site is located 270 km SSW from the area in which Lasse stayed for around a month.

8 December

Lasse has been in the same region for more than a month. The size of this area is only approximately five square kilometres. In the evening, he most probably slept somewhere close to locations 49-51. In reality, some of the apparent movements shown on the map are in fact caused by inaccurate satellite locations.

1-2 January

Lasse is still in the same area in which he arrived in the beginning of November. Now he was sleeping near the northern edge of the area (points 62-64 in Google Earth map).

9 February

Lasse is still in the same area (locations 86 to 88 at the Google Earth map). The transmitter was installed exactly six months ago.

3 March

On 9 February Lasse was still in the same area where he has been for three months. Quite surprisingly, locations of 14 February (numbers 89 onwards on Google Earth map) revealed that he had returned 270 km northwards to the area where he stayed in October. In early hours of 1 March he was still on that area. Lasse's spring migration will most likely start in the beginning of April. We can only hope that the battery has still enough capacity to show us Lasse's way back to Finland.

30 March

Lasse is still in northern Gabon.

13 April

No changes, Lasse is still in northern Gabon.

Spring migration 2011

18 April

Lasse’s spring migration started today! At 07.29 UTC he was still in the same area in which he has stayed for the last few weeks. At 09.09 he had traveled 14 km northwards, and at 11.15 he was still continuing his flight, now 50 km away from the starting point. The nearest weeks will be very exciting, because Lasse has started the very dangerous journey back to the breeding grounds, but also because the battery of the transmitter is running out at any moment. We can only hope that Lasse will survive and that we can still have a chance to follow his way back to Finland.

23 April

Early in the morning Lasse was sleeping in northern Nigeria, near the city of Madara. During the last four days he had traveled for almost 1,100 km. Next he will be facing the dangers of Sahara.

28 April

Since the last locations, Lasse has traveled for 1,600 km. He was now sleeping in Algeria, very close to the Libyan border. Before reaching the Mediterranean Sea, he still has to fly 800 km. Sadly, the data also indicated that the battery of the transmitter is likely to run out soon.

2 May

Quite unexpectedly, Lasse had continued to north and was located on the east coast of Sardinia in the evening, after having traveled for 1,550 km from the previous position in Algeria near the Libyan border. Thus, he was able to avoid the hunters in Malta and Sicily. Next time the transmitter will send data  on 7 May. Then Lasse will most likely be in the Balkan region, from which we did not receive any data during the autumn migration.

7 May

Lasse had arrived in continental Europe and was located in western Hungary near the Austrian border on late afternoon and evening. During the last few days he had traveled around 950 km. He still has to fly approximately 1,500 kilometres to reach his home in Kokemäki, western Finland. If the weather conditions are favourable, Lasse will be back at his nest during the next week.

12 May

Since 7 May Lasse had continued his journey to Poland. At noon he was located 130 km south-west from Warsaw (location number 24). During the next seven hours he flew towards north-east and ended close to the border of Kaliningrad. In this time he traveled approximately 340 km, on average 50 km per hour. Lasse’s route seems a little inconsistent, but this is due to the fact that 16 out of 21 locations were inaccurate. When Lasse started to rest in the evening, he was yet to travel 800 km to reach his nest.

17 May

Lasse had reached his nest in Kokemäki, western Finland! Most probably he had arrived there already on 15 May. Thus, his spring migration took exactly four weeks, during which he traveled around 7,000 kilometres. This corresponds to approximately 250 kilometres per day.