What 6488 did last summer

 Continuing our effort to fill in information from the adult Greater spotted eagle (6488) we have been tracking, I wanted to recap what it did during last summer.  

Although the eagle was an adult, it left Kuwait fairly late in the spring in 2020. When it left Kuwait, other Greater spotted eagles had already arrived on breeding grounds in Russia and started to nest.  Anyway, the tracked eagle did not breed during summer 2020.

After arriving on the breeding grounds (6 April), 6488 settled for some days near Turgay, Kazakhstan, then pushed farther north.  For the rest of the summer it wandered widely in west Kazakhstan and southern Russia, sometimes settling for some days, even weeks.  Its summer ranging lasted until 1 October (177 days).   Its final weeks during the summer were spent close to Turgay, where its summer had started.  

The size of the summer range was huge, but the estimated size of the range depended on the way the data were analysed.  Using a Brownian Bridge estimate of the home range, the eagle's summer range covered more than 27,000 sq km; using a kernel density estimate the home range covered over 238,000 sq. km.  See maps below. 

Brownian Bridge estimate of summer range of an adult Greater spotted eagle in 2020.

Kernel density estimate of the summer range of an adult Greater spotted eagle in 2020.

The graph below shows the variation in movement during summer (orange), which contrasts with the steady movement during spring migration (green), and the settled behaviour during winter (blue)

Movement of an adult Greater spotted eagle during 2020.  Orange is summertime, and shows the bird to be moving at times (e.g. in May), and being settled at other times (e.g. most of June).

The graph below shows the distance the eagle was from the starting point (Al Jahra) during the course of the year.  During winter (blue) it remained close to the starting point; during spring migration (green) it moved quickly away from Al Jahra, and during summer (orange) it wandered around Central Asia, sometimes moving away from Kuwait and sometimes moving toward Kuwait.

 

Awaiting migration of the Greater spotted eagle

The Greater spotted eagle we fitted with a tracking device in January 2020 is currently still at Al Jahra.  However, spring and migration are approaching.  In advance of that, here is a recap of what happened last year during the spring migration.

We fitted the GSE with a GPS/GSM transmitter (ID: 6488) on 15 January 2020 at Al Jahra Pools Reserves.  It spent the rest of the winter at Al Jahra.  Although tracking only covered part of the winter, it flew a total of 1993 km while at Al Jahra (Jan-March 2020).  Its average flight speed in winter during daytime was 1.94 ± 3.8 km/hr (median = 0.61). The wintering area was small, and restricted to the Al Jahra Pools Reserve and adjacent land.  Tracking data estimates that the eagle spent 99% of its time within only 3.91 km²

Map of winter ranging (Jan-Mar 2020) of an adult Greater spotted eagle at Al Jahra, Kuwait,  

The eagle remained at Al Jahra until 30 March, when it started migration. This is an adult bird, so it might leave earlier in 2021, if it is going to be a breeder.  It did not breed in 2020, but let's hope that it will this year.  

In spring 2020 it migrated to western Kazakhstan, near the town of Turgay (49.63N, 63.49E), where it arrived on 6 April, only 8 days after leaving Al Jahra. That migration flew 2847 km across southern Iraq, Iran, Turkmenistan, and into Kazakhstan.   Average speed on migration (daytime) was 26.69 ± 23.57 km/hr (max = 70.01, median = 30.52), and highest speeds were attained in the hours around mid-day (See graph below). The area near Turgay includes olive groves and sand dunes, and is near the Turgay River. The map below shows the migration route (green).

Movements of an adult Greater spotted eagle during 2020.  

The green line is its spring migration route.

The graph below shows the rate of movement during 2020. The blue is movement on the wintering grounds (very little), and green is the movement on spring migration (very rapid).

Movement rate of an adult Greater spotted eagle during 2020.

The graph below shows the rate of movement in relation to the time of day (hours after sunrise).  Blue is winter at Al Jahra; green is spring migration.  During spring migration it averaged around 60 km/hr around the middle of the day.

Tracking a steppe eagle - one year on

 Its been almost exactly a year since we fitted a transmitter to a juvenile Steppe eagle, and released it at Al Jahra, Kuwait.  For the last few days (since 27 February) it has apparently been in a GSM hole in Saudi Arabia, just south of Kuwait, and has not uploaded any data. 

In the most general of descriptions, after release this eagle wandered a bit during last spring, then migrated north along a path that took it to the west of the Caspian Sea and into Russia.  The summer was spent wandering around Russia and Kazakhstan. In autumn 2020 it migrated again to the west of the Caspian, and spent the beginning of the winter in SW Yemen.  During the latter part of the winter 2020/21 it started moving north rather slowly, stopping off for days at at time at locations in Saudi Arabia.  Below is a map of its journey from the time it was tagged until mid January 2021.

Map of the movements of a young Steppe eagle during March 2020 - January 2021.

The map below shows the more recent movements, and its last location just south of Kuwait.  We think that it has probably entered a GSM hole, not least because we endured a gap in data upload last spring when the eagle flew through this area.

Movements of a juvenile Steppe eagle during January - March 2021.