Vultures and other carrion eating birds in the Artificial Feeding Site, on mt Pinovo, Aridea, N Greece Lavrentis Sidiropoulos¹, Pantelis Konstantinou², Panagiotis Azmanis³ & Rigas
4 Tsiakiris
1: Olimpiados 18, 54632 Thessaloniki, Greece, e-mail:
[email protected]
3:Adelfon Pouliou 4, 54655, Thessaloniki, Greece,
2: “Chrysaetos” E. Group of Almopia, Garefi Aridea, Greece, e-mail:
[email protected]
4: Department of Ecology, School of Biology, Aristotle University, Thessaloniki,Greece , e-mail:
[email protected]
Introduction The transborder area of Aridea is situated in N Greece, in the borderline with FYROM. The trans-border mountains of Tzena, Pinovo, Kaimaktsalan and Paiko are designated SPAs and PSCIs in the Natura 2000 network and are regarded as very important for the conservation of Balkan biodiversity. 30 species of birds of prey (16 of them regularly breeding), including all 4 European vulture species. Griffon vultures visit the mountains from their breeding colonies in FYROM, ~ 40 km afar. A Bearded vulture and a Black Vulture survive as solitary individuals. Egyptian Vultures pairs breed sparsely alongside the border. In 2002, an artificial feeding site (AFS) for vultures and other birds of prey was established on Pinovo mt, at 520 m alt. by the National Agricultural Research Foundation, as part of an ongoing LIFE-nature project (Tsiakiris R: 2002). Since then it is supplemented and monitored by members of Chrysaetos (voluntarily and through a BVCF/FZS Balkan Vulture Action Plan project) and stuff of the forestry service of Aridea.
e-mail: azm_
[email protected]
Materials and methods Since the autumn of 2002, several disposals have been made with slaughterhouse offal and dead animals. Offal was monitored for the next 2-5 days, carcasses normally for 2-5 days in the following 10 day period. In total, 34 disposals have been made, followed by 99 days of monitoring. We examined the presence of the five most regular species by season, as a percentage of season observation days seen in the vicinity and inside the AFS (feeding)
Table 1: Distribution of disposals and subsequent monitoring by season Season Winter
No of disposals 7
No of observation days 14
Spring
8
30
Summer
8
16
Autumn
11
29
RESULTS
In total 12 species were found using the AFS, five of them quite regularly. These five species are Bearded Vulture (Gypaetus barbatus), Egyptian Vulture (Neophron percnopterus), Griffon vulture (Gyps fulvus), Golden Eagle (Aquila chrysaetos) and the Common Raven (Corvus corax). For the Bearded vulture, analysis included observation days even up to 20 days after the last disposal, since decomposition of food that affects the other species selection of food does not apply in bones Bearded Vulture (Gypaetus barbatus):
50 45 40 35 30 % of 25 observation 20 days 15 10 5 0
% Days feeding % Days observed
) 30
4) =1 (n in W ) 29 n= t( Au 6) =1 (n
m Su
n= r( Sp
Seasons
50 45 40 35 % of 30 observation 25 20 days 15 10 5 0
The bearded vulture was observed mainly during the spring months. Although the species was observed feeding only during spring and summer, it is very probable that it fed most of the days it was observed in the area. This was however very difficult to confirm since the species may remain in a feeding site for very short time, picking a bone and leaving unnoticed aided by the intense relief of the area (Tsiakiris R: 2001) . It appears around the feeding site, usually emerging unnoticed from below.
% Days feeding % Days observed
The pair that is known to breed in Pinovo mt is regularly observed in the feeding site and a nearby garbage dump. In several occasions however, up to three birds are observed, the third bird being not always the same bird (in total 2-4 individuals, identification based on plumage).
(n
)
4) =1
)
9) =2 (n
in W
t Au
30
6 =1 (n
= (n
m Su
r Sp
Season
Egyptian Vulture (Neophron percnopterus):
Griffon Vulture (Gyps fulvus): 35 30 25 % of 20 observation 15 days 10 5 0
% Days f eeding % Days observed
Su Season Spr ( Au m W n= t (n (n in 30 = =2 (n 16 ) =1 9) ) 4
)
Griffon vultures appear in the area mainly from midsummer until mid autumn. In late October 2004, a concentration of griffon vultures in a carcass near the AFS was followed by 5 disposals in 2 weeks, during which the flock remained in the vicinity until mid November and peaked in 22 individuals using the AFS (the maximum number ever recorded).
Golden Eagle (Aquila Chrysaetos): Photo 1: Pinovo mt, with Agiasma gorge and the Artificial Feeding Site highlighted
% Days f eeding % Days observe d
4) =1 (n
0 0 0 0 0 0 1
in W
0 0 0 0 0 0 1
9)
0 1 0 0 1 1 0
=2
2 0 1 3 1 1 1
% Days feeding % Days observed
Season
4) =1 (n in W ) 29 n= t( Au 6) =1 (n
2 1 1 3 2 2 3
80 70 60 50 % of observation 40 days 30 20 10 0
) 30
Winter
Corvus corax
m Su
Autumn
Common Raven (Corvus corax):
n=
Summer
The golden eagle is a regular visitor of the AFS, especially through winter and late summer – autumn, when breeding pairs and immatures are observed. The relative absence from spring to early summer coincides with incubation and first weeks of the nestlings. More than 2 pairs use the AFS.
Season
r( Sp
Black Kite (Milvus migrans) Black Vulture (Aegypius monachus) Common Buzzard (Buteo buteo) Long-legged buzzard (Buteo rufinus) Marsh Harrier (Circus aeruginosus) Imperial Eagle (Aquila heliaca) Hooded Crow (Corvus corone)
Spring
(n
Species
No of Days Observed Feeding
ut
Table 2: List of all species recorded using irregularly the AFS, during each time period
A
In table 2 a list is given from all other species recorded using irregularly the AFS. Apart from the Black vulture, the Imperial Eagle and the Marsh Harrier, the other species of the table are breeding in the area and were observed regularly at the vicinity of the AFS, throughout the study period.
6) =1
) 30
(n
= (n
um
S
pr
S
Other species:
80 70 60 50 % of observation 40 days 30 20 10 0
The common raven is the most regular visitor in the AFS and the one that appears in the highest numbers. It was observed almost in every feeding attempt, in flocks that reached up to 90 birds in one occasion. Raven populations thrive in the area (100-150 individuals), exploiting also the nearby garbage dump in the lowlands. Its densities peak from early autumn to late winter.
DISCUSSION and CONCLUSIONS
From the number of species observed and according to their conservation status the AFS of Pinovo mt is considered very successful (Alivizatos 2003). However, because of the irregularity of the disposals (there have been no disposals for as long as 5 months at times) the AFS has not yet achieved its full potential as a conservation tool for the conservation of vultures and other birds of prey in the area. For example in 2004, more than 15 griffon vultures remained for 20 continuous days in the area which was also their former breeding site (up until early 80s). The supplementation of the feeding site during this time was very difficult, since the slaughterhouse offal were either consumed or decomposed in the next 2 days and required immediate replacement. Due to lack of funds and logistic difficulties (the feeding site is accessible only through a forest road) the disposals where discontinued. This could be resolved with disposals of carcasses. A large cow carcass has kept a similar group of griffons for one week in the past in nearby pastures, “lasting” more than one week (Tsiakiris et al, 2002). Egyptian vultures also benefit largely from the Artificial feeding site and when the nearby garbage dump will close it will be their only constant food source. The occurrence of individuals of various ages suggests that new pairs may also form in the near future. Winter carcass availability can increase breeding densities of golden eagles (Watson et al: 1992) and enhance winter survival of immatures. More than one pairs have been so far observed in the AFS (Konstantinou et al), and immatures of various age. The AFS can enhance the populations of carrion eating birds in the area, if it functions properly through constant funds and support, as part of a larger transborder feeding site network. From so far gained experience, this requires 2 carcasses of large animals per month. References: Tsiakiris R, 2003: On the experimental creation of an artificial feeding site for the bearded vulture and other raptor species on the Mt range of Tzena and Pinovo. Unpublished report to NAGREF.(in greek) Konstantinou P, Sidiropoulos L and Azmanis P: Observations of birds of prey in the transborder mountain range of Aridea for the period 2002-2005, Unpublished Data Tsiakiris R, Kazanztidis S, Stara K, Azmanis P and Sidiropoulos L, 2003:Methods of selection and experimental implementation of artificial feeding places for vultures in Northern Greece. Poster presentation in the 9th ICZEGAR, Thessaloniki, Greece Alivizatos H. (2003). Provisions and requirements for the establishment and management of artificial feeding sites for raptors. Unpublished report .(in grrek).Ministry of Environment-Hellenic Ornithological Society Watson J., Rae S. R & Stillman R. 1992: Nesting density and breeding success of golden eagles in relation to food supply in Scotland. Journal of Animal Ecology: 61.3
