PICOTO: THE TRAVELLING HONEY BUZZARD – PART 2

“Picotin” the sole chick reared by Picoto in 2013m just days before leaving its territory.

Honey Buzzard (Pernis apivorus), juvenile, Valle del Jerte (Cáceres), 28th August 2013

Picoto, the first Iberian Honey Buzzard (Pernis apivorus) tracked by satellite, was the star of a popular posting in this blog which attracted even the press. On that occasion we told the story of his outward and return journeys between Spain and Liberia and of his travels in Liberia during the winter of 2012-2013. His next journey to Africa has also been the object of attention and the information obtained has been of great interest.

Covering 365 days, a complete year, from the first migration, the time spent migrating has been 33 days (9%), the time spent in Extremadura has been 111 days (30%) and the period in his winter home in the Liberia forests has been no less than 221 days (61%). In the two years of the study Picoto has occupied the same territories and the same nest, demonstrating that Honey Buzzard show a great faithfulness to both breeding and wintering areas.

Notwithstanding that the information is partial, Picoto’s movements in the Jerte valley were limited to a well-defined breeding territory, with some differences between the first part of spring (May – June, in the red circle and upper left map) compared with summer (July – August, green circle and upper right map). At the start, contact with Picoto was in the lower part of the valley, with no difference between the sunny and shady slopes. In the later months almost all of the activity was on the sunny slopes with a wider range of altitude, crossing the Jerte River towards the south on two occasions. Outside his territory, he only showed a short displacement down the valley to Rebollar and once outside the Jerte valley to Hervás.

Almost all of the contacts with Picoto were from within Pyrenean oak woodland (Quercus pyrenaica), which is a habitat under much pressure in the Jerte valley, having lost much of its area and quality over the last few decades, as a result of the unstoppable spread of cherry production. This photo of part of Picoto’s territory clearly shows the high level of fragmentation of the oak woodland. Given that Picoto spends seven months a year in the Liberian forest, his problems do not end here, as in Africa also there are threats to the forest, illegal logging for timber for example, which are even more serious.

The post-breeding migration in 2013 was very similar to that undertaken in 2012. Picoto left the Jerte valley on 29th August; in two days reached the Straits of Gibraltar and crossed to África on the morning of 31st August, crossing the 30 kms of open sea over the Atlantic and reaching the African coast next to Tangier. In 2012 he crossed the straits on the morning of 1st September, just a day later. Between the 2^nd and 7^th September Picoto crossed the Sahara, the second great geographic barrier that he had to encounter. After crossing the savannahs of the Sahel belt he entered more forested areas. Finally on 15th September he reached the wintering area, the jungles of eastern Liberia, after 16 days and 4,000 kms journey across Morocco, Algeria, Mauritania, Mali, Guinea and Liberia, flying over open sea, mountains, deserts, savannahs and forests. Since then, as in 2012, the signals from Liberia have been sporadic, presumably because the deep canopy cover of the forest there impedes the correct working of the solar-powered transmitter.

The data obtained agree with other studies carried out in Europe. For example, with eleven Swedish Honey Buzzards tagged, they show that the adults maintain, as does Picoto, small permanent territories in the African forest (stars), whilst the juveniles first of all spend some time in the northern zone of the forest belt and then move in the months that follow between 2,400 and 4,000 kms, without fixed territories or fixed travel direction and without return to Europe during their second year (Strandberg et al. 2012).

All of these findings have been possible thanks to SEO/BirdLife and the Junta de Extremadura. The work forms part of the Programa Migra of SEO/BirdLife.

Strandberg R., Hake M., Klaassen R.H.G. & Alerstam T. 2012. Movements of immature European Honey Buzzards Pernis apivorus in tropical Africa. Ardea 100: 157–162.

PICOTO, THE TRAVELLING HONEY BUZZARD

On a day just like today, exactly a year ago (26th July 2012), I had the chance to participate in the capture and marking with a satellite tracker, for the first time ever in Spain, a European Honey Buzzard (Pernis apivorus). The place: cool Pyrenean Oak woodland at 1,000 metres above sea-level on the slopes of the Jerte Valley in Cáceres province. The star: a male Honey Buzzard, we named Picoto. Here we can summarise a year in the life of an Iberian Honey Buzzard, thanks to the espionage that it was under. Photo above, by Domingo Rivera.

During the fist month, until 30th August when his southward migration started, Picoto successfully raised the single chick that was in the nest. Below, there is a photo taken on 9th August of his offspring, the not so small Picotín, who successfully left the territory several weeks later, in early September. 

The map shows the outward and return journey of Picoto, to his wintering grounds in Liberia. The southward journey took 17 days, from 3oth August to 15th September 2012. With a total of 4.085 km in a straight line, this means on average 255 km a day, with a maximum of 329 km. He stopped in La Janda (Cádiz) a day, crossing the Straits of Gibraltar on 1st September. On that very day, the largest number of Honey Buzzards of the season passed over Tarifa (Cádiz), more than 10,000 birds. Therefore Picoto was more than accompanied! Then he passed across Morocco, Algeria, Mauritania, Mali and Guinea, in a pretty much direct route across the Sahara desert.

The stay in Liberia was full of uncertainties, signals were barely being picked-up, with long gaps and always coming from a very restricted area. Suspicions rose that Picoto may have died and that the transmitter had become someone’s toy. But then, at last, after seven months of doubts, Picoto headed north again on 15th April 2013. The weak signals from October to April was probably because of the dense forest habitat where our Honey Buzzard was staying, with the canopy impeding the correct connection to the satellites. In the picture below, although some imagination may be needed, one can see the wintering area in the middle of the equatorial forests of Africa. 

Picoto’s return to his “home” in Extremadura was almost the same as his outward journey. It took just one day less (16 days) from 25th April to 10th May 2013. The journey was 200 km more (a total of 4,274 km in a straight line), with an average of 267 km a day, with the maximum considerable higher at 512 km in one day. The maximum altitude was 3,360 metres above sea-level and the maximum velocity was 41 kmph. The countries crossed were the same in reverse order: Guinea, Mali, Mauritania, Algeria and Morocco. On 8th May he crossed the straits and on 10th May was already occupying his nest from the pervious year in the Jerte valley. From then on, for reasons of security, the data from the transmitter are not available to the public, but Picoto has remained faithful to his nest site and is breeding normally, as you can see from the photo taken on 21st June, where he appears to be peacefully incubating. One can just about make out the antenna of the transmitter, with some down on its tip, coming from the back. 

Acknowledgements: Of course to long-suffering Picoto, involuntary collaborator, we hope for the benefit of all his species. A special thanks to Ivan Solana, the agent who found the nest and has been carefully monitoring Picoto and to Domingo Rivera and Ángel Sánchez, who are following the satellite data and who kindly have provided information about the adventures of our dear Honey Buzzard. In the capture and marking Javier de la Puente, José María Abad, Javier Caldera, Ángel Sánchez, Iván Solana and Domingo Rivera participated, along with a helper (Javier Prieta, who did very little apart from giving Picoto his name) and apologies a other collaborators whose names I do not know.

Translated by Martin Kelsey. 

THE HONEY BUZZARD IN EXTREMADURA (2009-2010)

Honey Buzzard (Pernis apivorus). Left: adult female with a honeycomb in its claws(Joel Brueziere, taken from Fat Birder). Right: adult male (Stephen Daly, taken from IberiaNature). Adults are distinguished by their yellow iris and tail with dark bars only at the base. Males have grey heads and lack the female's "tiger stripe" pattern running across the secondaries. The plumage of this species is very variable, ranging from very dark to very light forms through various reddish and brownish hues.

In 2009-2010 SEO/BirdLife brokered a national count of nine diurnal woodland raptors (Palomino and Valls, 2011). One of the species that came into this trawl was the Honey Buzzard (Pernis apivorus) [click for general survey aspects and methodology]. According to this survey Extremadura's population comes out as an estimated 43 territories (range 29-58), 36 in the province of Cáceres and 8 in the province of Badajoz. This represents only 2.3% of Spain's total population (1850 territories), way below the figures for Galicia (710), Castilla y León (510) and Asturias (280). The mean regional density was 0.10 territories per 100 km2, a long way below the national mean (0.37); the figure was much higher in Cáceres (0.18) than in Badajoz (0.04). As expected the highest densities were recorded in Atlantic Spain; the four Galician and Asturian provinces are the only ones clocking up a mean of 2 territories per 100 km2.

The Honey Buzzard has a local range in Extremadura, with at least 5 population clusters. The main one is in the Cáceres part of the Gredos mountain chain (La Vera and the valleys of Jerte and Ambroz), then stretching westwards to Tierras de Granadilla and Valle del Alagón. The second biggest nucleus occupies the Sierra de Gata and the third Villuercas. In Badajoz there are 2 small clusters, recently discovered, one in Cíjara and the other in Tentudía. In general, Honey Buzzards choose patchwork deciduous woodland and farming habitat in areas with rainy springs. Most of Extremadura's population nests in oakwoods (Quercus pyrenaica), although in marginal areas there are also territories occupied in Cork-Oak woods and pinewoods (Cíjara).
Predictive map of the Honey Buzzard's range in Spain (Pernis apivorus), taken from Palomino and Valls (2011). Notes: (1) The highest likelihood of a Honey Buzzard sighting in the whole country is in the Cáceres part of the Gredos mountain chain. (2) The five sites with proven nesting in Extremadura are marked in red. (3) The sectors marked in grey outside these areas have no known Honey Buzzard sightings in the breeding period. (4) The Tentudía site does not feature on the map.

The lookout counts showed Honey Buzzards to be especially common in the valleys of the Jerte and Ambroz rivers , where the likelihood of sightings is the highest in the whole of Spain. Densities sometimes build up to 9 territories per 100 km2. The vehicle transects were far less successful. In Extremadura as a whole an average of only 4 Honey Buzzards were seen every 1000 km, albeit with local sightings of 3 birds per 100 km in Jerte valley. Lastly, the Honey Buzzard population trend in Extremadura is unknown, although the trend is considered to be "possibly upwards" for Spain as a whole.

So much for the results thrown up by the SEO/BirdLife survey, carried out by volunteers and drawn from complex statistical calculations, all subject to a certain error. The survey authors themselves point out that the results are lower than previous estimates (in the cases of Madrid, Catalunya and Cantabria) and should be considered as minimum figures. The same goes for Extremadura, with previous estimates of 75 pairs. The actual population might well exceed 43 territories, for in Jerte valley alone the fieldwork showed up 25 possible territories plus 12 more in adjacent areas (J. Prieta, own figures). Such doubts are inevitable when dealing with a species so poorly studied in Spain as the Honey Buzzard, a highly idiosyncratic raptor because of its diet (bees and wasps) and its short stay among us (only from May to August). The sampling period was therefore very short and the sample itself was small (detected in Extremadura in only 10 of the ten-k grids with lookout points). Other aspects of the Honey Buzzard's behaviour makes them difficult to quantify: they pair off very quickly and their wing-clapping display flight period is also very brief; the significant non-breeding population (50-85%) is very visible sometimes with sizeable flocks; territories overlap; they range over large hunting areas (7-10 km from the nest) and they rarely betray their presence with any calls (Bijlsma, unpublished). Lastly, they are sometimes hard to tell apart from Buzzards (Buteo buteo), especially when a long way off.

The fieldwork was coordinated and carried out by SEO volunteers and personnel of the Environment Board (Dirección General del Medio Natural) of the Regional council of Extremadura (Junta de Extremadura).

Sources:
- Palomino, D., and Valls, J. 2011. Las rapaces forestales en España. Población reproductora en 2009-2010 y método de censo. SEO/BirdLife. Madrid. [download in PDF format]
- Bijlsma, R. B. Inédito. Abejero Pernis apivorus. Propuesta de método de censo. Informe inédito para SEO/BirdLife.

A WINTERING HONEY BUZZARD IN EXTREMADURA

Following a Wallcreeper blog entry published a few days ago we received an old Monfragüe Wallcreeper record. The list of birds furnished by the observer, Alan Parker, included an astonishing sighting of a Honey Buzzard (Pernis apivorus) at Salto del Gitano on the same day as the Wallcreeper (11 January 1989). The record is 100% reliable. Alan himself mentioned in his notes how totally unexpected it was to see a Honey Buzzard in January. There is no other Extremadura record at a similar date, though we're not sure whether or not the record is unprecedented at national or European level.

In Extremadura Honey Buzzards are summer visitors, arriving in early May and leaving by September. There have been occasional sightings in February (23 and 27/02/2000) and March (13/03/99 and 19/03/99). Source: Anuario Ornitológico de Extremadura.