Satellite-Telemetry

Autumn migration 2017 of Lesser Spotted Eagles

Copula of Lesser Spotted Eagles on the ground.

Autumn migration 2015 of Lesser Spotted Eagles began in September

Current status of Lesser Spotted Eagle autumn 2015 migration

In September all Lesser Spotted Eagles fitted with transmitters in Germany left the breeding areas.

The current course of migration is shown in rough terms on the  map. Comment on the migration and breeding progress of individual birds will be updated from time to time.

As at 18 October 2015, all birds with transmitters shown on the map had reached the African continent. 

The female (see detailed comments below and photos on German page) with transmitter number 41861 that has functioned since 2004, is not shown, as after such a long period of time, the transmitter performance has deteriorated and only irregular fixes are received outside Africa. The bird spent the night of 11/12 October high in the mountains in southern Turkey. It had overflown the Iskenderun Pass during the day.

Lesser Spotted Eagle breeding success in 2015 - we are still eagerly awaiting results!

In the meantime, we have unfortunately only received the figures for breeding success from the states of Brandenburg and part of Mecklenburg-Western Pomerania. The results for the rest of Mecklenburg-Western Pomerania, as well as abroad, are still lacking. We are still on tenterhooks as breeding success in 2015 was clearly very different from place to place.

Arrival of some Lesser Spotted Eagles at the breeding sites in spring 2015 was extremely late this year, although individual birds were already at their breeding site around 8 April. This followed a late start to spring migration with unusual stopover in Uganda and South Sudan. Too late an arrival at the breeding site, as also reported from other countries, can result in the pairs not starting to breed. We therefore await with great interest the remaining breeding results for Germany, as well as from other countries.

Some results for Latvia are now available (see below)

Results currently available:

According to T. Langgemach, 12 of the 24 pairs in Brandenburg bred successfully. That is quite a good result. Since 2009, the breeding success here is on average at only 20 % of the long-term mean.

In northern Western Pomerania (former District of Rostock) 37 territories were recorded in 2015. In these only seven pairs bred successfully. That is an extremely poor result for the year. Two pairs lost their offspring to predators before they could fledge. A further three pairs broke off their breeding attempt prematurely. Two of the breeding occurrences are new ones, although it seems that they have been present for a number of years. In 1991 and 1997, the breeding success was even smaller with four and five BP respectively with young. Wilfried Starke provided the information.

Thanks to Carsten Rohde, we can publish results from a further area on the western fringe of the distribution range (the Gnoien area, 420 km²). In 2015, 14 pairs were present and they raised six young. This is very poor in comparison to the year before when 13 young eagles fledged from 16 pairs.  2013, with only 3 young from 14 pairs. Since 1990, the number of pairs in this area fluctuated between 10 and 17, and the number of fledged young eagles between 2 (2002) and 13.

There are no figures available from other areas in Mecklenburg-Western Pomerania.  

Currently all eagles that we tracked on spring migration are still transmitting and all are fit and well. Almost all of the birds were also observed in the field during the breeding season and some of them were photographed. A tenth eagle, a now 15-year-old female, fitted with a transmitter in 2004, again bred at its old site (see photo on German page). The transmitter has now functioned for over 11 years, although now only in a limited manner, no wonder after such a long period.  The migration route is not shown, as the fixes were too irregular.

Three pairs near Burg Stargard (Mecklenburg-Western Pomerania), monitored by Axel Griesau failed to raise a young eagle in 2015. On pair were however observed feeding a young bird. It probably did not fledge, as in August there were no observations of either an adult bird carrying food, nor of a young eagle begging. In the case of a second pair, three adult birds were observed displaying in mid-May, but in two cases no nest was occupied. The third pair bred, but their attempt was unsuccessful, probably due to racoon activity. On 30 June, an adult bird was observed perched some 50 m from the nest, in which a racoon was sitting. On 2 July, a climb was made to the nest to look for evidence that the racoon was responsible for the loss of the young bird. Indications, but no hard evidence, was found. On 30 June, melt remains of possibly a young bird were found, but no fresh remains were found in the nest two days later, although racoon faeces were present.

It should be noted that plastic foil collars, which prevent racoons climbing to the nest, are affixed to the trunks of nest trees in Brandenburg. The NABU Federal Working Group on Bird of Prey Protection is more than happy to provide the plastic foil to Lesser Spotted Eagle nest wardens in Mecklenburg-Western Pomerania.

Latvia has one of the largest populations of Lesser Spotted Eagles. Data from U. Bergmanis for 2015 from random sites arrive at values of 0.37 young per pair present. The long-term mean value is 0.49 young per pair present.

As reported by Zdzislaw Cenian and Peter Radek, breeding success in northeast Poland was also extremely poor in 2015. As late as the end of May many eagles had not arrived on the monitored plot Warmia, in the north-eastern part of the Woiwodschaft Ermland-Masuren. Five of 49 breeding sites remained unoccupied. Nine pairs did not attempt to breed. Of 35 breeding pairs, only 11 (31 %) were successful. Such a low breeding success rate was recorded only once (1997) during 23 years of monitoring. It is assumed that, after a late arrival, many females did not lay eggs. Poor food availability with extreme dry climatic conditions also undoubtedly contributed to the catastrophic breeding results. Mortality of the young due to starvation was recorded in eight nests.

For reasons of time and space, the course of migration of Lesser Spotted Eagles (Aquila pomarina) only, and not the other species, are depicted, in cooperation with Birdlife Germany head office.  The presentation gives only a rough picture of the migration routes, based on one fix per day, in order to present the results in the internet as close as possible in real time. In fact, for some birds, hundreds of fixes were received daily.  This results of course in inaccuracies in some cases.

Migration within Germany is not shown, in order to guarantee anonymity of the nest areas of this extremely uncommon species.

There was not enough time available to evaluate the data, and depict the course of migration of other species fitted with satellite transmitters, such as Red and Black Kite.

The birds are identified individually by their transmitter numbers, and in some cases have been given a name, often by the nest warden.  A list of the Lesser Spotted Eagles follows with their transmitter number, name, and a few details on the bird itself. This information will be expanded at a later date. 

Click on individual birds to show or remove them from the map. Click on fixes to see more detail (date, time). Click on "Karte im Vollbild.Modus anschauen" (see below) to zoom the map.

Information on the individual eagles

220 = Ulf:

Autumn migration 2015: On 15 September 2015, shortly before  10.30 a.m.  (CEST), the departure of  a pair (Ulf und Marta) from the breeding site was recorded for the first time.

Breeding success 2015:  Despite late arrival the pair bred successfully and the young eagle fledged. The chick could not be ringed as the nest tree was too thin to permit climbing..

Background: The male bird was fitted with a transmitter of the latest generation, which transmits up to several hundred fixes daily, in summer 2013. Ulf was ringed as a nestling in Mecklenburg-Western Pomerania and is now (2015) 8 years old.

221 = Marta:

Together with its male partner Ulf, Marta left its breeding site on migration shortly before 10.30 (CEST).

Breeding success 2015: As in 2013 and 2014 the pair also reared a young eagle to fledging in 2015.

Background: This clearly very old bird was fitted with the same transmitter type as its mate on the same day. Marta's highest flight height on migration to date was recorded at almost 4,800 AMSL.

222 = Jan aka Bärli :

Autumn migration 2015: Departure on the morning of 7 September 2015.

Background: This male was fitted with a GSM tag in 2013. It bred successfully in this year. In both 2014 and 2015 however,  it arrived relatively late at the old nest site. On both occasions a new male was already present, on 2015 with an identification ring. In both years Bärli was unable to oust the newcomer. Thereafter Bärli visited many other nest sites in the wider surroundings and probably tried, unsuccessfully to settle elsewhere. In 2015 a fix was received from the centre of an existing wind farm where a dead Lesser Spotted Eagle had been found previously. Bärli fortunately survived unscathed.

52030 = Petra aka Peggy:

Autumn migration 2015:  Departure from the breeding site on the morning of 15 September 2015.

Breeding success 2015: Successfully raised a young eagle.

Background: This female was fitted with a transmitter in 2013 and occupied a nest near a planned wind farm. Peggy bred successfully in 2013, 2014 and 2015. The bird frequently visited the area of the planned wind farm.

84370 = Peter:

Autumn migration 2015:  Departure from the breeding site on the morning of 6 September 2015.

Breeding success 2015: The pair (Peter and Anna) successfully raised a young eagle that was ringed in the nest.

Background: This adult male has been tracked by satellite telemetry for a number of years. In 2014, it arrived back at the breeding site several days after its partner Anna (94758), which had bred with Peter for several years. Two days before Peter's arrival in 2014 however, Anna left the breeding site and bred successfully at another relatively distant nest site.

94743 = Rainer:

Breeding success 2015: Rainer arrived at the breeding site very late and either did not attempt to breed, or had no breeding success. Detailed information from the nest warden is not available.

Departure from breeding site on the morning of 15 September 2015.

Background: This male s fitted with a transmitter as a nestling in 2009 and had been tracked since. The bird is now (2015) six years old. It bred successfully for the first time at anew breeding site in 2014. In 2015 it arrived late at the beginning of May and had no breeding success. It is the very first Lesser Spotted Eagle to be fitted with a transmitter as a nestling and has been, since then, continuously tracked by satellite until its first breeding success at the age of five years.

94756 = Dieter:

Departure from breeding site on 18 September 2015.

Background: This male has been tracked by satellite for many years. In several of these years the eagle bred successfully. It is noticeable that the bird arrives late in spring and is always the last of the eagles with a transmitter to leave on autumn migration. In 2015 it departed however somewhat earlier as in previous years. The nest warden has provided no records of breeding success for this bird.

94758 = Anna aka Gabi:

Autumn migration 2015:  Departure from the breeding site on 5 September 2015.

Breeding success 2015: The bird did not breed as, on arrival, other females had already occupied both of its previous breeding sites. Some of the photos by Carsten Rohde appear to indicate a (temporary) injury to one eye, perhaps due to an altercation with one of the other females. It first arrived back at the newer of the two old breeding sites, but then 'commuted' between both broods and remained in close proximity (about 1 km) from either nest. In 2014, after moving to the second (newer) breeding site, and pairing with a new male, it bred successfully.

Background: This female bred successfully with Peter for several years but, as described above, left the old breeding site in 2014 and bred successfully, relatively distant, with another male. In 2015, it first returned to the new breeding site but was unable to expel the new female that was already present. It then flew to Peter at its previous breeding site; but here again a new female was already established (that subsequently bred successfully with Peter). Gabi/Anna was again unable to take back its nest from the new female. She will hopefully return in 2016 and we eagerly await the outcome.

95786 = Felix:

Autumn migration 2015:  Departure from the breeding site on 17 September 2015.

Background: This bird was fitted as a nestling with a transmitter in 2010 and has been tracked ever since. This represents the second longest known satellite tracking of a Lesser Spotted Eagle from the nestling stage. Again, in 2015, the bird did not breed, but continually visited other breeding territories in a wide radius. This is typical of some adult female Birds. It will be interesting to see where the eagle eventually settles. It will probably have to be given a new name, as it is now clear that it is a female. Male Lesser Spotted Eagles occupy a fixed territory as early as two years before they first breed.

After arrival in spring the Lesser Spotted Eagle is easily attracted to food bait, which must not necessarily be wildlife. Supermarket chickens appear to be a popular choice. After the long, strenuous journey to their breeding site the birds are ravenous. As there is usually a food shortage at this time, and the eagles begin egg-laying within a remarkably short space of time,  this additional feeding - if it is systematically conducted over a short space of time - can indeed influence the number of eggs laid and subsequent breeding success. This has been proved in studies of other birds of prey.

Subsequent to transmitter fitting, female 41861 paired with at least two males. In 2004, the male partner was simultaneously fitted with a transmitter and marked at the same time with a yellow plastic ring. The male did not return to the breeding site in 2005. A male reappeared again in 2007 and continued to do so every year to date. As the bird is unmarked however, it is not clear if it is always the same bird.

For the past few years only metal rings are used in Brandenburg that are often readable on flight photos. It is strongly recommended that plastic rings are not used as they only have a limited life.  In the case of a young eagle, the ring was lost, or more probably removed by the bird, during the begging phase.

(Text: B.-U. Meyburg)

(Photos: automatic wildlife camera Dr Günter Heise)