In this study, pre and post-construction data collected in 4 Portuguese wind farms was analyzed, in order to

identify changes in species abundance throughout the years. Additionally, it was also analyzed data

collected in other 2 wind farms, but which survey programs only covered post-construction years (Figure 1).

Attesting bird displacement in Portuguese

wind farms

Trondheim, Norway, from May 2 to 5, 2011.

BERNARDINO, Joana; MARQUES, Ana Teresa; SILVA, Maria João; FERREIRA, Rita; ZINA, Hugo;

MASCARENHAS, Miguel and COSTA, Hugo

Bio3 – Estudos e Projectos em Biologia e Valorização de Recursos Naturais, lda. Rua D. Francisco Xavier de Noronha, 37B. Almada, Portugal.

(joana.bernardino@bio3.pt)

Introduction & Methods

Conclusions

Results

Figure 1 – Location of the wind farms considered in the analysis.

Giving the exponential increase of turbines installed worldwide, a great number of bird surveys have been

conducted in wind farms. However, few study analyzed data collected through different survey programs,

regarding disturbance or displacement.

In order to compare results among different years, Bio3 performed, each season, survey points within the

Wind farms and Control areas. All birds seen or heard at each point, during a 5 minute period and till a

distance of 100m, were recorded. Variation in species abundance was analyzed using a Generalized

Linear Mixed Model (GLMM).

• Just one specie, the Common Blackbird (Turdus merula), showed a

clear decreasing trend on both post-construction years, in opposition to

control areas;

Table 1 – Evolution of 10 species abundance on post-

construction years 1 and 2, comparing with the baseline year

(Pre-construction). (WF – Wind Farm, CO – Control areas;

significance: .

0,1≤ p < 0,05; * 0,05 ≤ p < 0,01; ** 0,01 ≤ p < 0,001;

*** 0,001 ≤ p < 0)

CO

WF

Troglodytes troglodytes

CO

WF

Turdus merula

CO

WF

Sylvia undata

CO

WF

Serinus serinus

CO

WF

Sylvia melanocephala

CO

WF

Emberiza calandra

CO

WF

Lullula arborea

CO

WF

Fringilla coelebs

CO

WF

Carduelis cannabina

CO

WF

Alauda arvensis

Year 2Year 1AreaSpecie

**

.

**

.

***

*

.

**

**

**

*****

Pre and post-construction analysis

Table 1 presents the results of the 10 songbird species most commonly found in the 4

windfarms considered:

• Apparently, Linnet (Carduelis cannabina) and Wren (Troglodytes

troglodytes) populations also suffered from displacement during

Year 1, although they seemed to habituate to wind turbines

presence after this initial period;

• The remaining 5 species revealed no significant differences between years or areas,

meaning that no displacement effects were detected.

Post-construction analysis

The results of this analysis, which compared Year 2 and 3 with the 1st Year of surveys after

construction, support the overall findings of the previous analysis:

• The results obtained for the species Skylark (Alauda arvensis) and Corn Bunting (Emberiza

calandra) also suggested a possible negative effect on their populations, although more

years of surveys would be needed to validate these preliminary results;

• T. merula populations decreased consistently over the years;

Considering the 10 songbird species analyzed, the Common Blackbird (T. merula) seems to be the specie most affected

by the presence of wind turbines. In opposition, the Chaffinch (F. coelebs) and the Dartford Warbler (S. undata) continue

to equally use the wind farm areas after construction. Nevertheless, further research is needed, always including pre-

construction data and control areas, in order to corroborate these preliminary results.

• After 1 or 2 years, the abundance of C.cannabina and T. troglodytes in

wind farms areas increased;

• No significant differences were detected on A. arvensis, Fringilla coelebs

(Chaffinch) and Sylvia undata (Dartford Warbler) populations.