The 2003-04 Results

Unfortunately our plans for tracking honey buzzards, both adults and young, from the Highlands of Scotland are on hold because we were unable to find suitable nesting pairs. 2003 was a poor year for the species in our study area. Reports suggest it was also poor in some other studied populations in mainland Europe. In our case, we wondered if it might have been due to very dry conditions in April and May in the Highlands causing a scarcity of active frogs which are a favourite early food when the honey buzzards return from Africa.

We did find a new nest, with two young, but it was too late in the season to catch either an adult or the young, as the chicks were already branching out of the nest on the day we visited the tree. The nest had two young, and we watched an adult bringing food to the nest on several occasions. Two young flew and our local contacts tell us that the last young was thought to emigrate on 19th September.

Although our plans have centred on studying honey buzzards in the Highlands on Forestry Commission land, we had identified that it would be important to compare the migrations of young from a nest in England with our North Scottish birds.

We were very pleased that the group who study honey buzzards in SE England offered us the opportunity to satellite track two young from a nest they knew. We are grateful to English Nature and the British Trust for Ornithology for permission to fit the transmitters. I was taken to a nest site on 16th August and fitted the radios. The group reported that the young were flying on 22nd August and remained in the nest area into September. The older chick stayed in the general area of the nest, within 10 kilometres until migrating, but the younger chick moved about 25 kilometres where it remained. Both young migrated across the English Channel on 23rd September.

In order to maintain confidentiality of the nest site, the starting co-ordinates for the migration journey are given as Heathrow Airport which are 51 28'N 00 28'W.

The following data shows the migration for each chick, which was regularly updated throughout 2003. The younger chick wintered in Guinea and then moved to Liberia, but the batteries in its radio gave up during January 2004; the older ones radio stopped transmitting in Mali on the autumn migration, again due to loss of battery power.

ENGLISH HONEY BUZZARD JOURNEYS
 

E21251

This was the larger chick and had been ringed GP28865. A standard satellite transmitter of 20 grams was fitted on 18th August. This was a pale headed chick in very good condition with a wing length of 303mms. The chick along with its younger sibling (see below) was watched perched near the nest on 24th August. It was eating on the nest on 31st August and perched nearby. It was seen close to the nest on 4th and 6th September. It was not observed after 6th September but radio transmissions on that day showed that it was 1.3 kilometres from the nest site in the evening. Most  radio fixes were not accurate at this stage as the young bird was keeping well down in the woodland,  but by 20th September it was living about 10 kilometres from its nest, and it was still in the same area on 22nd. It started its migration on 23rd September as a cold front came down from the north when  there was snow in Scotland and frosts in parts of England. Its migration journey is shown below.

The young honey buzzard stayed for about two weeks around the nest site and then moved  to nearby locations for a further two weeks before migrating. This young had been flying for about 33 days when in started its autumn migration.

At 0342GMT on 24th September, this bird was 40 kilometres SE of Le Mans in France, presumably  roosting in the Foret de Berce as four hours later there was a signal from the same area. It clearly  flew across the English Channel and on into France on 23rd September, the same day as its sibling. At 2313GMT on 25th September, it was in wooded country just south of Dax, in south-western France  after flying 474 kilometres in two days - an average of 238 kilometres per day. It is now  very close to the western end of the Pyrenees. On evening 27th, a poor quality signal suggested the bird was just over the Pyrenees in Navarra, northern Spain; just 76 kilometres further south in  two days but the weather has been cloudy, with rain forecast. A series of brief signals during the  morning of 29th, with none of any accuracy, suggests it was in deep wooded valleys. Another  poor quality signal at 0400GMT on 1st October and also on 2nd was from the an area about 30 kilometres north of Zaragoza. On the afternoon of 4th October, a poor quality signal near Cartagena on the SE coast of Spain showed that the bird had reached the Mediterranean and was heading for Africa. A day later the younger chick was only about 50 kilometres behind its older sibling.

At 0833am, 6th October the bird was in the vicinity of Sidi Bel Abbas, Algeria, just inland of the  North African coast. This is due south of Cartagena and suggests that the bird flew 200 kilometres straight across the Mediterranean sea; the distance from the 4th October position is 222 kilometres. Young honey buzzards are known to fly across open water more than the adults which tend to go to the narrower crossing at the Straits of Gibraltar. Early morning two days later, on 8th October it  was heading into the mountains north-west of Tendrara in Morocco, having covered nearly 300 kilometres from Sid Bel Abbas.

By 2256GMT on 9th the bird was approaching the Erg Er Raoul Plateau in Algeria. It had flown 405 kms in two days and was well north east of Tabelbala On the evening of 11th October, it was  over sand deserts NE of Bordj Fly Ste Marie. This morning, 13th October, poor quality signals came  in for a position in the Sahara Desert south east of Chegga, in Mauritania.

This is 411 kilometres from its position on 11th so it is migrating steadily over the deserts in fresh  easterly winds. Unfortunately, the only signal received during the early hours of the 15th was  poor quality and no position was received. The bird was probably roosting out of direct radio view of  the satellite. Transmissions on 17th and 22nd were also of poor quality.

Today, I have looked at the latest signals in detail, and conclude from the activity sensor that the young honey buzzard is alive but the battery strength is falling and we may not receive any more  accurate transmissions from this radio. No more news from radio which has stopped transmitting.
 

E28661

This was the smaller chick and had been ringed GP28864. A standard satellite transmitter of 20  grams was fitted on 18th August. This was a dark coloured chick in very good condition with a wing length of 293mms. The chick along with its older sibling was watched perched on branches near the nest on 22nd and 24th August. On 31st it was perched in a nearby tree and then see flying on to occasions. It was not seen on 4th September or 6th September but radio transmissions on the 7th showed that it had moved over 35 kilometres away. It stayed in that general area until 22nd September. It started its migration on on 23rd September, exactly the same day as it sibling, as a cold  front came down from the north when there was snow in Scotland and frosts in parts of England.

Its migration journey is shown below and will be updated.

The younger honey buzzard stayed for about two weeks around the nest site and then moved  about 35 kilometres to a new location where it spent over two weeks before migrating. This young  had been flying for about 33 days when in started its autumn migration. An examination of the most accurate fixes showed that it lived mostly in an area of about one square kilometre within a  large woodland. On 10th September it roosted about 3 kms west of this area and on 13th it roosted
3 kms to the east, but one the nights of 18/19th, 19th/20th and 20/21st it was in the same place  within the most used locality.

This bird flew across the English Channel on 23rd September and was located moving at sea over the English Channel at midday; by mid afternoon it had reached the French coast near Le  Havre. It continued into France and by 5pm local time was north of Alencon, where it probably  roosted for the night in the Foret d'Ecouves. By late afternoon of the following day it was 25
kilometres north of La Rocehlle after a day's flight of about 280 kilometres. On the 25th, it continued southwards over France and by night had flown 158 kilometres and was roosting north  of St Andre on the Dordogne, north of Bordeaux. Next day it flew a further 97 kilometres but headed  more to the SSE and was roosting at night near St Michel de Castelnau, heading into a valley
 leading to the mountain chain of the Pyrenees. The present weather conditions of low cloud and  rain will not encourage it to cross the mountains. On 27th, it flew 125 kilometres further south, moving a little west during the day. At 8am on 28th, the bird was near Marlanne, east of Orthez  and by the morning of the 29th it was near Huesca in Spain.

During the 28th the young honey buzzard covered at least 174 kilometres and it appeared to  cross the Pyrenees at one of the high passes at the head of the Vallee d'Aspe. The pass is at 1632 metres above sea level (5300 feet). On the 29th, in light NE winds and good conditions, it covered 174 kilometres in the morning and by midday was near Used, near Daroca, with an
accurate location at 1021 GMT near the Embalse de las Torcus. The younger chick has now overtaken its older sibling by taking a more eastern and higher route over the mountains. Midday,  on 30th September, it had reached Galamocha and continuing south. Poor signals on 1st October were from a similar area.

On 2nd October, it was near Pozondon, north of the Sierra de Albarracin and overnight on  3rd/4th October it was near Bunol, West of Valencia on the Meditteranean coast after a migration of 142 kilometres. The following night, 0324GMT on the 5th October, the young honey buzzard was near Orihuela, just NE of A Murcia having covered 144 kilometres. It was just 50 kilometres of where its older sibling had been the previous day. Both birds should cross into Africa over the  next few days.

At 0813am, 6th October, it was just inland of the Algerian coast, near Ghazaouet, just north of Ahfir, eastern Morocco. It was 363 kilometres from its previous position and must have  made the crossing of the Mediterranean Sea on the 5th, either a 300 kilometres flight from Cartegena in a SSW direction, or possibly down the coast to Cape de Gata and a 180 kilometres direct south flight to North Africa. It is very interesting that both chicks are keeping up with each other although not travelling together. Weather conditions have been good with light to fresh  NE winds, clear visibility, cloudy with sunny spells in the western Mediterranean.

Two signals on 7th October showed that it was actively migrating into Africa near Ain Beni Mather in Morocco, having travelled 97 kilometres from the previous day's position. By early  afternoon it had travelled a further 138 kilometres in about 4 hours and was west of Tendrera.  It was now ahead of its older sibling but surprisingly close in the same region. Just over 24 hours
later, on 8th October, it had flown a further 185 kilometres south and was west of Bechar, having crossed back into Algeria. Late afternoon, on 9th October, the young honey buzzard was migrating south over the deserts of Erg er Raoul in Algeria in calm and hot sunny conditions with a temperature of 30C. By midnight, it was in the northern desert of the Sahara, well south east of Tabelbala, Algeria having covered 277 kilometres since yesterday.

On 9th October, positions were received from the Argos tracking station for the older chick  E21251 at 2256GMT and for the younger chick E28661 at 2254GMT. It is incredible that they  are only 97 kilometres apart after a journey of 2500kms. Overnight on 10th/11th October the bird  was 202 kilometres further south in sand deserts near Hassi Bou Bernous. Twenty fours later
 it was 148 kilometres further south near Grizim in Algeria. On 13th October, it was south of the  Mali border, north of Tmaza and had flown a further 243 kilometres in fresh easterly winds.

Early afternoon on the 14th the young honey buzzard was in a most remote part of the deserts  called the El Djouf in eastern Mauritania. It had flown an amazing 600 kilometres since its position early on the 13th. By the following late afternoon, 15th October, the bird had just about completed  its crossing of the Sahara and was east of Aoundaghost in southern Mauritania. heading south  through the Sahel towards the Montagne de l'Affole. This was a further 282 kilometres.

It has already flown 3872 kilometres in 23 days giving a daily average 168 kilometres per day. Overnight on 16th/17th October, the bird was in Niora in western Mali and overnight on 17th/18th October very good signals from Diema, western Mali. Overnight on 18th/19th October it was near Lac de Marantali, Mali after a day's migration of 209 kilometres. Next day it flew 105 kilometres and early morning on 20th it was west of Kabaya. A day later in the morning of the  21st it was near Tamba, Guinea having travelled just 33 kilometres to cross the border. Last night, 22nd October it had migrated a further 90 kilometres and was near Dinguiray in Guinea. It was still in the same area on 26th and 29th October, so it has either halted its migration or found a suitable place to winter.

Signals through to 25th November from same area and the bird has stopped its migration.  The location of the wintering area appears to be in the headwaters of the river Niger. This  place is 4581 kilometres from its nest area in SE England. The radio has now switched to a  10 day interval, so up dates will be less frequent.

No signals received on 5th December but after dark on 15th December, poor quality signals  came in from an area on the Ivory Coast/Liberian border in the coastal district. This place is 805 kilometres south-east of Dinguiray in Guinea. Poor quality signals are likely to be due to the  honey buzzard living in dense forest which makes it difficult for the satellite to fix the bird's  position. In view of the poor quality signal, I waited for another set of transmissions. Overnight  on Christmas Day, the bird was roosting in forests south east of Buchanan in Liberia. This is 263 kilometres northwest of the birds position 10 days earlier and is 610 kilometres from  its original wintering area. Both these sets of data are poor quality so the positions may  not be accurate but undoubtedly the young honey buzzard has moved and is now in the coastal  region of Liberia. A very similar position was given on 5th January 2004 so the bird is now in a second wintering area. Poor quality signals on 15th and 25th January and 4th February gave no  accurate locations, but the bird was alive. The battery is now exhausted and we are unlikely to
 get any more useful data. But this bird's journey has been most interesting and has told us more  about the ecology and migration of the species.