by Jincy Varughese
Recently, multiple airports in the US have installed photovoltaic (PV) solar energy systems in large areas of undeveloped grasslands commonly found on their grounds. The potential environmental and economic benefits have been well documented but to date there has been no research on the effect such systems will have on birds. DeVault and a team of researchers from the US Department of Agriculture and Mississippi State University begin filling this knowledge gap by comparing bird use of PV arrays to that of nearby airport grasslands.
DeVault et al. (2014) observed bird patterns for one year in five locations where PV arrays were near airports. The researchers established bird survey transects at the sites and conducted at least one morning and one afternoon survey each month at each transect. Bird usage and interaction with the airfields and the PV arrays were documented but birds simply flying through the transects were not included in the final analysis. Additionally, in order to analyze whether the PV arrays attracted a larger biomass of birds, a bird hazard index (BHI) was calculated by multiplying the number of each species of bird observed in a transect by its expected mass and then summing up the values for each species observed in the transect.
The researchers found that there was no difference in BHI for the airfields with and without PV arrays, demonstrating that the presence of PV arrays does not alter bird usage, at least when measured by biomass. On the other hand, twice as many birds but fewer species were observed at the PV arrays than at the airfields. This is consistent with other research that large scale solar development is harmful to wildlife diversity. Additionally, DeVault et al. did not find that birds were attracted to the light reflected by the PV panels nor did they observe any collisions with the PV structures. A comparison of seasons shows that BHI was greatest in the summer, reflecting increased bird usage of PV arrays for perching and shade. In fact, most of the observations of PV array transects involved small birds perching on panels. Small birds are not very hazardous to aircraft and small birds that are perching as opposed to flying, are even less hazardous. This suggests that in some locations, implementing PV arrays can actually decrease the risk of bird strikes in comparison to grassy airfields.
Devault, Travis L., Thomas W. Seamans, Jason A. Schmidt, Jerrold L. Belant, Bradley F. Blackwell, Nicole Mooers, Laura A. Tyson, and Lolita Van Pelt. “Bird Use of Solar Photovoltaic Installations at US Airports: Implications for Aviation Safety.” Landscape and Urban Planning: 122-28. [GSSS: airports pv bird use aviation safety]