5.4 Necropsy of white-tailed eagle
5.4.1 Material and methods
From August 2005 until September 2010, 44 adult dead WTEs have been recorded in connection with wind turbines in the Smøla and Hitra wind-power plants, 39 and 5 specimens respectively.
The eagles from Hitra were collected in 2006, 2008 and April–November 2009. Three of the five Hitra specimens are included in the study. Eagles found before 2007 have been examined earlier (Follestad et al. 2007). The carcasses were of different value for post-mortem examination. Some specimen had been killed quite recently, while others were more or less free of soft tissue and quite desiccated. Thus, the condition of a majority of the carcasses did not allow for a thorough and classic autopsy. Nevertheless, all eagles were x-rayed. The objective of the x-ray picture ex-amination was to reveal fractures of the skeleton. x-ray pictures were taken mostly with birds lying on their back.
5.4.2 Results
The findings in connection to each of the 29 eagles found after April 2007 are listed in Table 7.
The majority of the x-ray pictures showed extensive skeletons damages, and 20 of the eagles were actually cut in two or more pieces. The findings of Follestad et al. (2007) were similar. Sev-eral of the eagles described as birds cut into two or more parts showed additional fractures.
These fractures are not counted for as single fractures in the table.
Table 7. Post mortem findings of dead white-tailed eagles collected in connection with two wind-power plants in Central Norway. TN=wind turbine number. The age of each WTE specimen is given in calendar year (K) (see Figure 42 for details on bone nomenclature).
WTE number
Location TN Age Post mortem findings
002 Hitra 23 5 cy The remains of the eagle were quite putrid. The left wing was cut from the body at articulatio humero-scapularis. The joint between humerus and radius/ulna was distorted. Bones from both feet and pelvis (os ilium and ischium) were found separated from the rest of the body. The fractures of the feet (tibiotarsus) were very cleanly cut.
003 “ 23 Ad. Only bones and no soft tissue left, the eagle was almost overgrown with vegetation. The eagle had obviously died more than a year ago. Bones were found spread around the finding spot. Fractures were found in os radius and ulna of the left wing.
004 “ 03 2 cy The eagle was in a good state of nutrition. Right wing was cut off at the carpal joint. Radius and ulna have bone fractures all along the bones. Fragments of bones aligned like pearls on a necklace. Size of the fragments was 1-2 centimetres.
12A Smøla 25 4 cy Parts of a cadaverous eagle. The body was cut in a tilted trans-verse plane, midway across the body. Angle of impact from the front and sidelong towards os sacrum. Left wing showed fracture and dislocation of fragments in radius and ulna. Bones were splin-tered. Right wing showed multiple fractures in humerus. Multiple fractures and dislocations in the neck bones (cervical vertebra) especially near the head and breast aperture.
12B “ 25 4 cy This was the cut off part from SE 12 A. Picture showed fracture of left femur, knuckle parts dislocated from each other. Small part of posterior part of the pelvis (caudal vertebrae) was present.
14 “ 52 Ad The eagle was in good state of nutrition. Found relatively fresh with no signs of cadaverosis. x-ray pictures show a fracture in the left clavicular bone. A wound, 7 centimetres in diameter, ventrally on the neck a little to the left of the midline. Extensive haemorrhages along the whole neck.
15AB “ 64 Ad Relatively cadaverous body. Left wing without damage. Right wing had multiple fractures in radius and ulna, numerous pieces of bones with sharp edges. The neck was cut of (not present) at the breast aperture and at scull basis.
16BC “ 61 10 cy The eagle was in good state of nutrition. The right wing was cut off from the body, found apart. The left wing showed fracture near articulatio humero-scapularis. Dislocation of knuckle fragments.
Right leg showed numerous fractures near articulatio femoro-tibiotarsus (knee). The same findings could be seen in the left leg.
The head was found separated from the body, as well as the neck bones (one piece).
17AB “ 37 Ad Macerated eagle cut in two pieces. Cutting line was from front of sternum towards kidney region. No damage to the left wing. Right wing attached to the body has multiple fractures in both humerus and radius/ulna; see Figure 41 A. Fractures in both legs, dislo-cated bones. Os ischium also fractured. Considerable external force applied to the body has been exerted. Figure 41 B show disintegrated bones.
18 “ 38 4 cy Eagle in good nutritional status. X-ray without remarks. The beak shows a fracture in the lower part of the beak. The injury prohibits normal use of the beak. The fracture must have been caused by an external force applied to the beak.
19 “ 30 Ad The carcass was quite putrefied. Scarce amount of soft tissue was present. Right wing shows fractures in humerus (upper arm) near the shoulder. Numerous loose fractured bones. Several disloca-tions of bones. Multiple fractures in radius/ulna of the left wing, distally of the carpal joint. Both legs cut off from the body, small part of femur left on the legs.
ian for a fracture near metacarpus in the left wing. The eagle did not recover and was euthanized. One buckshot pellet found in breast muscle (x-ray diagnosis).
21 “ 31 Ad An eagle in good nutrition status. The left wing was found 75 me-ters away from the rest of the body. Cut off near the shoulder joint.
No other findings.
22 “ 09 3 cy Eagle in good condition. Left wing cut off in the middle of humerus.
No other findings.
23 “ 68 5 cy Almost no soft tissues left. Cadaverous.
24 “ 24 4 cy Fairly good condition. Distal part of right wing missing, cut off. Nu-merous fractures in radius/ulna distally on bones.
25 “ 21 2 cy Eagle in good condition. X-ray shows multiple fractures of the right humerus (upper arm) near shoulder joint.
26 “ 20 2 cy Eagle in good condition. X-ray shows multiple fractures of the right wing. The same picture present in the left wing. One buckshot also found in the left wing. Multiple fractures of the pelvis. The skull is crushed, columna near the skull separated from the rest of the neck.
27 “ 06 1 cy The body found cut in 2 pieces. Scavenged. Transversal cut in the middle of the body. Fractures of both legs in femur and tibia.
28 “ 47 Ad Female eagle in normal condition, fresh. Blood in beak and throat.
Extravasations in skin on the scull and in periost of scull. Internal organs subject to bleeding, some blood in the body cavity. Multiple fractures in right wing, one in the middle of os humerus and two in ulna. Left wing without findings.
29 “ 01 Ad Eagle in good condition. Left wing cut off in the middle of humerus.
No other findings.
30 ” 01 4 cy+ Almost no soft tissues left. Cadaverous.
31 “ 04 Ad Fairly good condition. Distal part of right wing is missing, cut off.
Numerous fractures in radius/ulna distally on bones.
32 “ 59 3 cy Eagle in good condition. X-ray shows multiple fractures of the right humerus (upper arm) near shoulder joint.
33 “ 25 Ad Eagle in good condition. X-ray shows multiple fractures of the right wing. The same picture present in the left wing. One buckshot found in the left wing. Multiple fractures of the pelvis. The skull is crushed, columna near the skull separated from the rest of the neck.
34 “ 26 5 cy The body found cut in 3 pieces. Scavenged. Transversal cut in the middle of the body. Fractures of both legs in femur and tibia.
35 “ 42 2 cy Eagle in good condition. Left wing (radius/ulna) cut off. Fracture of humerus in the right wing. Also multiple fractures in the reminders of left ulna.
36 “ 24 6 cy Eagle with no soft tissue left. The body cut in 2 pieces in the chest region, 10 cm from the breast aperture. A thin slice of skin keeps the body parts together. X-ray shows fracture in the middle of the right tibia.
37 “ 53 3 cy Cadaverous eagle. Left wing cut off in the humero – ulnaris joint.
The wing found separately. Fracture of tibia right foot.
38 “ 21 3 cy Totally scavenged, no soft tissue left. Left wing cut off in the elbow joint (articulatio humero – ulnaris). The body cut in 2 pieces trans-versally across the chest right behind the scapular bones.
WTE 2 WTE 12
WTE 17 A+B
WTE 22 WTE 24
Figure 41. X-ray images showing some typical injuries of white-tailed eagles killed by operating wind turbines in the Smøla and Hitra wind-power plants, Central Norway.
A B
Table 8. Post mortem findings (fractures and their localization) in dead white-tailed eagles col-lected in connection to two wind-power plants in Central Norway.
Bone Number of birds with fractures
Radius and ulna (underarm) 13
Humerus (upper arm) 16
Phalanx 1
Femur (leg bone) 12
Tibiotarsus (lower leg) 13
Cranium 1
Sternum (breast bone) 1
Scapula (shoulder) 1
Cervical vertebra (neck) 3
Caudal vertebra (back of pelvis) 4
Thorax (breast) 2
Sternum (front of breast) 1
Clavicle (clavicular bone) 1
Carpal bone 3
Rostrum (beak) 1
Figure 42. Drawing of bird skeleton with total number of fractures (all eagles) indicated by ar-rows.