Satellite tracking of Migrating and Wintering adult Eastern Imperial Eagles

Satellite tracking of Migrating and Wintering adult Eastern Imperial Eagles (Aquila heliaca) In memory of our friend Patrick Paillat, without whom this study would not have been possible in Saudi Arabia and who died a few months ago.

Adult male in the hand

Bernd-U. Meyburg & Christiane Meyburg

The Eastern Imperial Eagle is a very rare species.

Still very little is known about the migration and wintering of this species apart from birds breeding in Europe.

Imperial Eagle perched

Typical wintering habitat in Arabia

Imperial Eagles were often found among Steppe Eagles

Between April 1994 and November 2003 eight Imperial Eagles were trapped at their wintering site near Taif in Saudi Arabia and fitted with satellite transmitters (PTTs).

Young Imperial Eagle

with an adult Steppe Eagle

The first three birds in 1993 and 1994 were fitted with batterypowered PTTs, four birds in 1995 – 2001 with solar-powered PTTs and one bird in 2003 with a solar-powered GPS tag

Six eagles tracked were adults, four males and two females.

Two more eagles were immature birds.

One of them was a very big female which was probably four years old.

Most eagles were tracked for periods of one to one and a half years.

An immat. eagle was shot after only three weeks in Saudi Arabia and an ad. male after one year in Kuwait.

Two birds were trapped three times and another eagle twice.

Probably most eagles removed the PTTs after a certain time period.

Handling of the Imperial Eagles and fitting of the satellite transmitters (PTTs)

So far this is apparently the only study of adult Imperial Eagles.

Patrick Paillat

Patrick about to release an adult

The trapped eagles were easy to handle when hooded

Release of an adult bird

An ad. Imperial Eagle just released with a PTT

One of the two immature birds was shot after only three weeks in Saudi Arabia.

Russia China Kazhakstan

Arabia

Six eagles were tracked up to their breeding areas and in most cases back again to Arabia.

Four birds came from Russia and one eagle each from Kazhakstan and China

The distances between summer and winter areas were between 3900 and 5000 km

The spring migration routes of all six eagles

The spring migration routes of the three female eagles

A four year old female still in immature plumage weighed 4800 g, thus it was much heavier than any known individual from the literature. This bird was fitted with solar-powered PTT 23671 and tracked from 9 March 1995 until 17 March of the next year.

China

Its migration was the longest, over 5,000 km, and in the most eastwestern direction of all the birds. Its summer area was in Xinjiang Province in northwestern China close to the borders of Mongolia and Kazakhstan.

Spring migration of the four year old female with PTT 23671 to China

In autumn 1995 the bird (PTT 23671) returned to the same general wintering area in Arabia

In winter 1995/96 the bird ranged over a large area near Taif and Mecca (Makkah) in Saudi Arabia

In the spring of 1996 the female with PTT 23671 was tracked on almost the same route in the direction to China, but contact was lost in Kazakhstan shortly before its arrival.

The spring migration routes of the three adult male Imperial Eagles

Ad. male (3.050 g) was first captured in Arabia on 20 December 1992. On 28 February 1994 it was recaptured at the same place and fitted with a battery-powered PTT (21820). It was tracked until 28 December 1994. It had a summer home range of about 2000 sqkm (max. diameter 100 km) some 250 km WNW of Ufa, Russia. We suppose that it was not breeding or that it lost its brood in an early stage.

Ad. male 21820 summering in Russia some 250 km WNW of Ufa

Another adult male which was caught on 17 October 1995, fitted with a solarpowered PTT (26047) and tracked for a year until 6 October 1996 when it was still in Kazakhstan. One month after its last location it was shot in Kuweit apparently by American soldiers. We got the PTT back through the German Embassy.

Probable nest site of ad. male 26047 in Kazakhstan

An ad. male (3100 g) was trapped on 1 March 1994 and fitted with battery-powered PTT 21819. It was tracked until 17 August 1995.

The bird was breeding in Bashkyria in European Russia west of the Ural Mountains in a small group of four poplar trees 12 m above the ground and few hundred meters from a farm. The pair was known to the farmer for at least one decade. In 1995 and 1996 the pair was breeding again at the same site.

The eyrie contained two nestlings on 13 June 1994. It was situated at almost 56° N at the northern edge of the range of the species in European Russia.

Spring migration route of the adult male with PTT 21819 to Bashkyria in European Russia

Satellite image of the breeding area with good (LC : 2 and LC : 3) Doppler locations

The location of the nest site

The male was trapped again on 23 November 1994 at the wintering site.

Since the PTT was still working, it was released without changing it.

On 31 January 1996 the eagle was caught for the third time at the wintering site. The transmitter which had stopped sending signals on 17 August 1995 was not attached to the bird any more.

On 23 November 2003 we used for the first time a 65g GPS tag. An adult male was fitted with this PTT and tracked until 17 February 2004.

A lot of information was gathered on the wintering behaviour of the bird, since the PTT not only transferred exact GPS positions of the eagle, but also on altitude, flight speed and flight direction.

Red Sea

The GPS fixes of the wintering ad. male eagle in Saudi Arabia

The wintering home range of this ad. male had a size of 5.900 sqkm, extending over 127 x 29 km

Habitat use and 95% minimum convex polygon home range (3.690 km²)

Kernel analysis of the winter home range

Between 19 h in the evening and 10 h in the morning the eagle was only located perched and not flying.

Most often the eagle was flying in the afternoon between 15 and 17 hrs.

This species has a strong tendency to remove transmitters. Shortly after departure in spring the eagle removed the transmitter when still in Saudi Arabia.

The eagle had bitten through the harness made of stainless steel with a soft coating. Before we had use teflon as harness material.

Thank you very much

This research was carried out at the National Wildlife Research Center Research near Taif, Saudi Arabia.

for your attention