Milvus migrans

Temesvary, Peter, Heinz, Dr. Walter & Gundert, Martin, 2013, Additional Assessment Report - Crucea North Wind Farm 99 MW, Constanta County, Romania: European Bank for Reconstruction and Development (EBRD) : 169-170

6.3.6 Black Kite ( Milvus migrans )

Black kite 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 6.12 below.

No black kite nests were recorded during breeding surveys undertaken in 2013, although a single bird was recorded poisoned within the Allah Bair-Capidava SPA. During the VP surveys black kites were only recorded on two occasions, with individual birds recorded on each occasion.

The CRM calculated at the most conservative avoidance rate of 95% that one black kite would be killed every 40.2 years and at a more realistic avoidance rate of 99% that one black kite would be killed every 201.2 years (see Annex C).

Average adult survival has not been estimated for black kite but is likely to be similar to that of the closely related red kite which has been estimated at 0.61 (12). The Romanian breeding population is relatively small and has been estimated at 120-160 pairs, with a declining population trend (13).

Although the SPA breeding populations of black kite are 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 black kite as a result of collision mortality. As with long-legged buzzards 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 black kite. However given the very low number of flights recorded during the VP surveys, significant effects from foraging habitat or disturbance during construction and operation are not predicted.

There is the potential for barrier effects on migrating black kite, however the Crucea North Wind Farm site has not been reported to support any important migratory routes in the context of the wider area and is not know to generate important thermals for migratory birds (Wildlife Management 2012). This conclusion is supported by the results of the 2013 VP surveys. As a result no barrier effects are predicted. Overall no effects to the integrity of any of the SPAs are predicted as a result of effects on the qualifying interest features black kite populations.

It should be noted that birds of prey have no avoidance of poisoned bait and that this is likely to have a much greater impact on breeding bird populations than mortality related to wind farms.

The overall black kite flight activity was 1.23 x 10-7 hrs/ha/hr, amounting to 4.79 x 10-4 hr/hr over the whole site.

Black kites 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

Black kite occupancy ( n) of the wind farm area is, therefore, estimated to be 1.03 hours per year during the observation period (4.79 x 10 -4 x 2157.3).

6.1. 2 Number of Transits of Black Kite 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 black kite of 0.58m.

The bird occupancy of the volume swept by the rotors in seconds ( b) is:

( n x 3,600) x (Vr/Vw)

= ( 1.03 x 3600) x (1,547,028.04/4,682,040,000)

= 1.23 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 blach kite (0.58m) and v is the speed of the bird through the rotor (11.7 ms-1) (36), = 0.39secs.

The number of bird transits through the rotors per season is b / t = 3.14

6.1. 3 Estimating Collision Likelihood

Using the SNH spreadsheet, and assuming a black kite flight speed of 11.7 m/s, the model predicts that an average of 19.8% of black kite flights through the rotor swept area would result in collisions. This was reduced to 15.84% to allow for non operating time.

The number of birds predicted to collide with the operating rotors over the season is 0.50 birds per year during the observation period (3.14 x 15.84%). 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 40.2 years during the observation period at 95% avoidance or a bird every 201.2 years at 99% avoidance.