Our studies of honey buzzards in the Scottish Highlands continued this year. For the second season, the Forestry Commission and the Highland Foundation for Wildlife joined forces to try to understand the migration and ecology of this elusive species. Last year, we fitted satellite transmitters to two juvenile honey buzzards. This year, the same pair of adult honey buzzards returned to their usual nest and reared one young.
The summer was very changeable, after an early spell of good weather in May, heavy rains and cold weather periods were not ideal for a species whose main summer food for its young is wasp grubs. Between us, we located three nests, but two failed, probably at the small young stage. This year we were eager to place transmitters on adult birds and find out if experienced birds migrated towards the short sea crossing between England and France, rather than risk the more westerly routes through the western parts of the United Kingdom or even into Ireland. We decided to try to catch one of the adults at the main nest site. On 5th August, we caught the adult male who is a most distinctive and very pale individual.
Adult Male 53481
General
This bird was ringed GF 53481. The measurements were: wing length 410 mms, tail 253 mms and weight 785 grams. He was in excellent condition. We fitted one of the new generation satellite transmitters (number 21253) which use the new Argos 2 satellite system and a manufacturer’s refinement called SiV (Satellite in View). This should give more accurate signals during migration. On release he flew off strongly and joined the female who had been flying over head (she was a dark brown individual).
Annual Movements
The bird remained around the nest for two weeks after his chicks had fledged, and set off on his migration on 5th September. He crossed the English Channel on the 11th September, having made a very direct journey through the UK, as would be expected from an experienced migrator. We don’t know if he arrived in Africa through the Gibraltar Straits or if he took an alternative route, but by the 20th September he was in Morocco. He then headed through Algeria and Mali and by 2nd October had reached Ghana, just 28 days after he set off from Scotland. He then migrated through Nigeria and rested for 10 days. From there he headed into Cameroon and then Guinea, and then reached his wintering grounds in Gabon on 30th October. The last signal was received on 22nd March and we had to conclude that the battery had run down.
To read further details of the adult male’s migration click here: Adult male 21253
Reproductive History
In the time that we knew him, this male reared 3 chicks (2 in 2001 and 1 in 2002).
Juvenile 21250
General
The single chick of the above adult male and its mate was ringed in its nest on 10th August 2002 and fitted with satellite transmitter no. 21250. This bird has the same parents as the two chicks tracked in 2001. Despite the rather poor wet weather, the chick weighed 1010g and was well fed with wasp grubs. Its wing length was 292 mm so we expected it to remain in the nest for at least another ten days.
Annual Movements
Its male parent left on 5th September when the chick was still located in the nesting wood. On the 10th it roosted about 10km away but then returned to its natal site, until 15th September when it was located south of Inverness. At this time, the mornings were foggy but afternoons and evenings were sunny with clear skies under high pressure. The bird set off well but got blown off course into the seas of SW Ireland. Incredibly, the chick managed to keep going without hitting land and we hoped it might manage to reach Spain, but sadly it missed the Azores. By this stage it had flown constantly for at least three days without stopping or feeding, an amazing feat for a chick that had only just learned how to fly. Sadly, the exertion proved too much for it, and it must have drowned in the sea. We received no more signals after 8th October.
To read details of the juvenile’s migration click here: Juvenile 21250
Reproductive History
Chick 21250 did not reach breeding age during our studies.
