POPULATION TRENDS OF THE COMMON QUAIL (Coturnix coturnix) IN FRANCE AND SPAIN: CONFLICTING DATA OR CONTROVERSIAL CENSUS METHODOLOGIES?

Transcription

1 POPULATION TRENDS OF THE COMMON QUAIL (Coturnix coturnix) IN FRANCE AND SPAIN: CONFLICTING DATA OR CONTROVERSIAL CENSUS METHODOLOGIES? Puigcerver, M. 1, Eraud, C. 2, García-Galea, E. 1, Roux, D. 2,Jiménez-Blasco, I 1, Sarasa, M. 3 & Rodríguez-Teijeiro, J.D Universitat de Barcelona, Spain. 2. Office National de la Chasse et de la Faune Sauvage, France. 3. Fédération Nationale des Chasseurs, France.

2 SOME FEATURES OF THE COMMON QUAIL Migratory and nomadic Galliformes species. Current conservation status: Least Concern (BirdLife International 2017). Population trend: it appears to be decreasing (Birdlife International 2017). It is very difficult to census (Gregory et al. 2005, Phil. Trans. R. Soc. B 360: ). It is a huntable species in some Mediterranean countries. Source of controversy between hunters, conservationists and wildlife managers

3 TRYING TO CLARIFY POPULATION TRENDS Census in: Four breeding sites of France ( ). Two breeding sites of NE Spain ( ). ACTIVE METHOD The whole France ( ), ACT method. Prats, NE Spain ( ), SOCC method. PASSIVE METHOD

4 -Prats

5 ACTIVE METHOD Vs PASSIVE METHOD ACTIVE METHOD: It counts males responding to a digital female decoy. 10 count points spaced by at least 700 m. Once a week throughout the breeding season. Specific design for the Common quail. Local scale survey (2-4 breeding sites) PASSIVE METHOD (ACT SURVEY): It counts only males singing spontaneously. 5 point counts spaced by 1km. Based in just one day throughout the breeding season. It has a general design for 17 breeding species. Large-scale survey (the whole France) INTENSIVE BUT LOCAL METHOD WEAK BUT WIDESPREAD METHOD

6 PASSIVE METHOD PASSIVE METHOD (ACT SURVEY): Only data from mid-may to mid- June was analysed. Counts performed outside a presumed window of availability were discarded. Routes where Common quails were never detected since 1996 were discarded. Routes surveyed less than 10 years were also discarded. PASSIVE METHOD (SOCC) 6 count points spaced by 500 m. All the bird species detected are censused. Data from two days (one between 15th April-15th May and another between 15th May- 15th June). Second census must be done at least 15 days later. Census in good meteorological conditions. From sunrise to next 4 hours.

7 ANALYSES Generalised Additive Mixed Models with poptrend R-Package. Active method data: Quasi-Poisson error distribution and log link function. Number of detected males: response variable. Date and Site : factors. Year : covariate and random factor. Passive method data: Negative binomial distribution. Number of detected males: response variable. Year, Date and Counting hours : covariates. Site and Year : random factors.

8 ACTIVE METHOD-Vs PASSIVE METHOD (I) Catalonia, NE Spain (Alp and Figuerola del Camp) The whole France (ACT survey)

9 ACTIVE METHOD Vs PASSIVE METHOD (II) France (Montbel, La Cavalerie, Sault and L Ariège) Time window: Space window: degrees longitude East and South of 44 degrees North.

10 THESE RESULTS GENERATE SOME DOUBTS Are Common quail stable in Catalonia but declining in France? Are the differences found in our results due to the different census methods applied? Am I decreasing or am I stable???? A more exhaustive analysis is needed!

11 IN THE 21-YEARS PERIOD OF ACT SURVEY IN THE WHOLE FRANCE In most sites and years there are no quails or there are very few ones

12 DIVIDING THE DATA SET BY ABUNDANCE Places in which quails have been detected from 1 to 7 times in 21 years Places in which quails have been detected from 8 to 14 times in 21 years Places in which quails have been detected from 15 to 21 times in 21 years Bad quail habitats Bad-intermediate habitats Good habitats

13 PASSIVE METHOD Relationship between the total counts in a given place and the probability of at least one detection (number of years from the total 21- years period that quails are detected in one site). Relationship between the probability of detection and the mean count when there is at least one detection. COMPATIBLE WITH A DENSO-DEPENDENCE SCENARIO

14 ACTIVE AND PASSIVE METHODS MAY NOT CENSUS THE SAME THINGS Population trend in Prats (passive method) Population trends in Alp (active method) Relationship between Prats census and Alp census When there are 3 quails or less, Catalan passive method censuses zero individuals

15 CONCLUSIONS In good habitat sites of Catalonia (NE Spain), by using an active census method, no trends have been observed. In the whole France, by using a passive method, a decreasing trend has been observed. However, in good French habitat sites for the Common quail, no trends are observed. Results obtained when using the passive method in France are compatible with a scenario of denso-dependence. It may provoque a lack of detectability when quail abundance is low. Active and passive methods could be unrelated. These results strongly suggest that more studies (i.e. INLA analyses) must be carried out in the near future, in order to inequivocally determine the Common quail population trends in France.

16 THANK YOU VERY MUCH FOR YOUR ATTENTION!