Buteo rufinus
publication ID |
https://doi.org/10.5281/zenodo.17263512 |
persistent identifier |
https://treatment.plazi.org/id/038087C0-FF42-FF0F-FF7C-056DC7D6F845 |
treatment provided by |
Julia |
scientific name |
Buteo rufinus |
status |
|
6.3.5 Long-legged Buzzard ( Buteo rufinus View in CoL )
Long-legged buzzard is a qualifying interest feature of Allah Bair – Capidava SPA, Cheile Dobrogei SPA, Stepa Saraiu-Horea SPA, and Stepa Casimcea SPA. The populations for each are shown in Table 6.11 View Table 6.15 below.
Two possible breeding locations for long-legged buzzard were recorded during the 2013 breeding bird surveys. One approximately 3.5 km to the east of the Crucea North Wind Farm site close to the edge of the Cheile Dobrogei SPA, and one approximately 6 km south of the Crucea North Wind Farm site within the Allah Bair – Capidava SPA. The birds recorded at both of these nest locations are likely to form part of the SPA populations.
During the VP surveys only single birds were recorded, with a total of 12 contacts across all VPs.
The CRM calculated at the most conservative avoidance rate of 95% that one long-legged buzzard would be killed every 22.1 years and at a more realistic avoidance rate of 99% that one long-legged buzzard would be killed every 110.48 years (see Annex C). Average adult survival for long-legged buzzard has not been estimated but is likely to be similar to common buzzard, at 0.9. The Romanian breeding population is relatively small and has been estimated at 65-110 pairs, with an increasing growth trend (11).
Although the SPA breeding populations of long-legged buzzard are relatively small, given the very low collision mortality calculated by the CRM, it is predicted that there will not be any effects on the SPA breeding populations of long-legged buzzard as a result of collision mortality. It is likely that adult birds will produce more than enough young to occupy suitable breeding territories within the SPA with the additional very low level of predicted mortality.
The construction of the Crucea North Wind Farm will result in the loss of some areas of foraging habitat for breeding and potentially for migrating longlegged buzzard. However the area of habitat lost to each turbine is predicted to be approximately 2.6 ha per turbine or 95 ha in total. This level of land take is not predicted to have a significant effect on the available foraging area for long-legged buzzard breeding in nearby SPAs, as there is abundant alternative foraging habitat within and close to the SPAs. As a result no effect on the integrity of any SPAs from loss of habitat or disturbance during construction and operation is predicted.
During the 2013 surveys of Crucea North a total of 14 long-legged buzzards were recorded. During the 2008/2009 surveys of the wider Crucea area, a total of 6 long-legged buzzards were recorded in spring, 5 were recorded in autumn and 3 were recorded over winter. Surveys of the Crucea East Wind Farm estimated a population of long-legged buzzard within the site of 1-10 individuals (Generacion Eolica Dacia SRL 2011).
As with kestrel, the 2008/2009 results from the wider Crucea area and information from Crucea East Wind Farm suggest that the numbers of Long-legged buzzard which use these sites is relatively low in relation to the numbers recorded at Crucea North. Given the low collision mortality rates predicted for Crucea North of 0.01 birds per year based on 99% avoidance, even with multiple sites with a similar collision risk, the in-combination collision risk mortality would still be a fraction of 1 bird killed every year. This level of mortality is not considered to be likely to have an effect on the breeding or migratory populations of long-legged buzzard within any of the SPAs for which it is a qualifying interest feature and therefore no effects on site integrity are predicted.
The overall long-legged buzzard flight activity was 2.25 x 10 -7 hrs/ha/hr, amounting to 8.78 x 10 -4 hr/hr over the whole site.
Long-legged buzzards were present on the site throughout the observation period, amounting to 153 days and they were presumed to be able to fly for an average of 14.1 hours daylight per day, a total of 2157.3 hours
Long-legged buzzard occupancy ( n) of the wind farm area is, therefore, estimated to be 1.89 hours per year for the observation period (8.78 x 10 -4 x 2157.3).
4.1. 2 Number of Transits of Long-legged Buzzard Through the Rotors
The size of the flight risk volume (Vw) is 4,682,040,000m 3. The combined volume swept out by the turbine rotors (Vr) is 1,547,028.04m 3 using a body length for long-legged buzzard of 0.58m.
The bird occupancy of the volume swept by the rotors in seconds ( b) is:
( n x 3,600) x (Vr/Vw)
= ( 1.89 x 3600) x (1,547,028.04/4,682,040,000)
= 2.25 bird-secs.
The time taken for a bird to make transit through the rotor and completely clear the rotors ( t) is (d + l)/v, where d is the depth of the rotor blade from front to back (4), l is the body length for buzzartd (0.54m) and v is the speed of the bird through the rotor (11 ms-1) (34), = 0.42secs.
The number of bird transits through the rotors per season is b / t 5.41
4.1. 3 Estimating Collision Likelihood
Using the SNH spreadsheet, and assuming a long-leggeduzzard flight speed of 11 m/s, the model predicts that an average of 20.9% of buzzard flights through the rotor swept area would result in collisions. This was reduced to 16.72% to allow for non operating time.
The number of birds predicted to collide with the operating rotors over the season is 0.91 birds per year (5.41 x 16.72%). This assumes no avoiding action is taken by the birds.
Avoidance rates were calculated as for kestrel. Mortalities were calculated using avoidance rates of 90%, 95%, 98% and 99% to provide an indication of potential risk (see Table 1.4 below).
This equates to a loss of a bird every 22.1 years during the observation period at 95% avoidance or a bird every 110.48 years at 99% avoidance.
Common name: Long Legged Buzzard.
Compiled from data in Table 4 View Table 4 , Table 4 View Table 4 , and Table 4 View Table 4 .
8 ex.; Romania, Constanta County, Crucea , lat: 44.533, long: 28.233; 2013-03-15 - 2013-05-31; ( Table 4 View Table 4 ) GoogleMaps • 6 ex.; Romania, Constanta County, Crucea , lat: 44.533, long: 28.233; 2013-06-01 - 2013-07-31; ( Table 4 View Table 4 ) GoogleMaps • 6 ex.; Romania, Constanta County, Crucea , lat: 44.533, long: 28.233; 2009-03-15 - 2009-05-31; ( Table 4 View Table 4 ) GoogleMaps .
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
Kingdom |
|
Phylum |
|
Class |
|
Order |
|
Family |
|
Genus |