# A proposal on bird focal species selection for higher tier risk assessments of plant protection products in the EU

## TL;DR

This paper proposes a new method to select bird species for risk assessments of pesticides based on their vulnerability, using survey data as a proxy for exposure.

## Contribution

A novel approach using frequency of occurrence in surveys as a proxy for dietary exposure to rank bird species by vulnerability.

## Key findings

- A positive correlation was found between frequency of occurrence in surveys and dietary exposure estimates.
- The new ranking approach yields similar focal species as the 2009 EFSA method, but identifies a few additional species.
- The proposed method provides a practical way to implement vulnerability-based selection when detailed exposure data is lacking.

## Abstract

The revised EFSA 2023 Guidance on the risk assessment of plant protection products for birds and mammals emphasises vulnerability as a relevant criterion for focal species (FS) selection rather than prevalence. The EFSA 2023 Guidance suggests to rank FS candidates for each dietary group according to their expected exposure by estimating a species-specific daily dietary dose (DDD). Species experiencing higher exposure would be ranked as potentially more vulnerable and can be identified as FS candidates. The DDD is calculated using an estimated “proportion of diet an individual obtains from the (treated) crop” (PT). A PT is derived from a radio-tracking field study in the crop of interest, but such data are not available for all species. We introduce the frequency of occurrence in surveys (FOsurvey) in each study field from FS field studies as a proxy for PT in theoretical DDD calculations. The presence of a species during a high proportion of surveys, resulting in a high FOsurvey, could indicate a high proportion of foraging time spent in this crop. To evaluate whether FOsurvey is an appropriate proxy for PT, empirical PT values from radio-tracking studies for different bird species were correlated to respective FOsurvey values from FS studies in the same crop and growth stage. Based on 10 case examples covering different species and crops, a positive correlation was shown between PT and FOsurvey, supporting the suitability of the proposed approach. Based on a positive correlation between the species’ prevalence and the new theoretical DDD, the list of the most relevant FS resulting from the new ranking approach is not expected to differ significantly from the FS selection, according to the methodology proposed in EFSA 2009. However, in a few cases, additional species were identified as potential FS, therefore requiring further consideration in the risk assessment.

Key points
The revised EFSA 2023 Guidance Document on the risk assessment of plant protection products for birds and mammals emphasizes vulnerability as a relevant criterion for focal species selection rather than prevalence, but provides unsatisfactory guidance on how this should be implemented.Here, we investigate an approach that uses the frequency of occurrence in surveys from focal species studies for daily dietary dose calculations to rank species according to their vulnerability to exposure and select the most vulnerable species as focal species.Based on 10 case examples covering different species and crops, the suitability of the proposed approach was shown.The most relevant focal species resulting from the new ranking approach are not significantly different from the focal species selection according to the methodology in EFSA 2009; only in a few cases, additional species were identified as potential focal species and require further considerattion.

The revised EFSA 2023 Guidance Document on the risk assessment of plant protection products for birds and mammals emphasizes vulnerability as a relevant criterion for focal species selection rather than prevalence, but provides unsatisfactory guidance on how this should be implemented.

Here, we investigate an approach that uses the frequency of occurrence in surveys from focal species studies for daily dietary dose calculations to rank species according to their vulnerability to exposure and select the most vulnerable species as focal species.

Based on 10 case examples covering different species and crops, the suitability of the proposed approach was shown.

The most relevant focal species resulting from the new ranking approach are not significantly different from the focal species selection according to the methodology in EFSA 2009; only in a few cases, additional species were identified as potential focal species and require further considerattion.