5.2. Ecology and monitoring of target waterbirds

Ecology and monitoring of waterbirds 

The monitoring of breeding colonies of waterbirds may provide valuable information for the conservation of both waterbirds and wetlands. Monitoring is essential in order to be able to determine the population trend of a species at a particular site. Moreover, in the case of endangered species, such data can be used to decide on any management intervention and, later, to assess the effect of that intervention. Also, monitoring of breeding populations of waterbirds can greatly improve our level of understanding of their ecology, as well as their role in the ecosystem. 

Waterbirds in Prespa

The Prespa Lakes are home to substantial populations of many rare and threatened waterbird species. Prespa’s importance was acknowledged in the late 1960s, when European ornithologists discovered the area. Later on, in the early 1970s, conservation work began and the need to monitor biodiversity was apparent. The Prespa lakes are important for waterbirds at national and international level, as they hold the largest Dalmatian pelican (Pelecanus crispus), colony in the world, the largest pygmy cormorant (Microcarbo pygmaeus) and great white egret (Ardea alba) colonies in Greece, and significant numbers of other rare and threatened waterbirds. A remarkable biodiversity is found within an area that is only 11 km long, while Prespa also has another very particular feature: it is a transboundary area, shared by three countries. 

Monitoring Prespa’s waterbirds

One of the key objectives of monitoring efforts in Prespa is to understand the role of waterbirds in the lake ecosystem, as well as their interactions with other aspects of this ecosystem, such as fish, shallow water habitats, aquatic vegetation, water quality and human activities. This objective was deemed to be crucial, especially as, from the early 1970s onwards, conservationists had become aware of the changes being brought by the gradual abandonment of traditional land uses around the shore of the lake, and how these affected important habitats used by waterbirds. Having acknowledged the complexity and importance of these interactions, the Society for the Protection of Prespa (SPP) has been carrying out research and monitoring on waterbirds since its establishment in 1991.

LIFE Prespa waterbirds monitoring work

As part of the LIFE Prespa Waterbirds project, the SPP has set up a monitoring scheme for nine waterbird species, all of which nest in the reedbeds of Lesser Prespa Lake: the Dalmatian pelican, the great white pelican (Pelecanus onocrotalus), the pygmy cormorant, the great white egret, the little egret (Egretta garzetta), the night heron (Nycticorax nycticorax), the squacco heron (Ardeola ralloides), the glossy ibis (Plegadis falcinellus) and the ferruginous duck (Aythya nyroca). This scheme is being employed in order to establish whether the project’s management interventions have benefitted the target species. It involves monitoring the annual breeding population size of each species, the breeding success of selected species, and the use of managed feeding areas by waterbirds throughout the breeding cycle.

Monitoring of the use of managed areas as feeding grounds

The main methods for monitoring waterbirds used by the SPP are: direct counts from vantage points, the use of a drone, flight-line counts for the mixed pygmy cormorant-heron colonies, and colony visits. All the methods have some limitations and their pros and cons will be briefly discussed in the presentation. 

Flight-line counts in Lake Lesser Prespa 

Other waterbird species and the transboundary dimension

In addition to the LIFE Prespa Waterbirds target species, the SPP also carries out systematic monitoring on other species of importance for the area, such as the goosander (Mergus merganser), the greylag goose (Anser anser) and the great cormorant (Phalacrocorax carbo). Many of these activities take place at transboundary level, usually involving co-ordinated censuses in the three countries. A further example of transboundary collaboration is the longstanding annual mid-winter count of wintering waterbirds, carried out simultaneously in all three countries. The PrespaNet partners have also participated in an annual census of pelicans in SE Europe, established by the SPP and carried out in eight countries in the region.

Suggested further reading

Efrat R., Harel R., Alexandrou O., Catsadorakis G., Nathan R. 2019. Seasonal differences in energy expenditure, flight characteristics and spatial utilization of Dalmatian Pelicans Pelecanus crispus in Greece. Ibis 161; 415-427. https://onlinelibrary.wiley.com/doi/10.1111/ibi.12628 

Catsadorakis, G. and Portolou, D. (compilers). 2018. International Single Species Action Plan the Conservation of the Dalmatian Pelican (Pelecanus crispus). CMS Technical Series No. 39, AEWA Technical Series No. 69, EAAFP Technical Report No. 1. Bonn, Germany and Incheon, South Korea.

http://www.trackingactionplans.org/SAPTT/downloadDocuments/openDocument?idDocument=32 

Society for the Protection of Prespa, 2017. Assessment of the population status, habitat use and phenology of the target species. Report within the framework of the project “LIFE Prespa Waterbirds”(LIFE15NAT/GR/000936).

https://www.prespawaterbirds.gr/img/edb699b48fd306476362e036ecba5222lifeprespawaterbirds-actionA2-SPP.pdf 

Catsadorakis G., Avramoski O., Bojadzi A. & H. Nikolaou. 2016. The status of an isolated population of Goosander Mergus merganser in the Balkans. Wildfowl (66):159-175. https://www.researchgate.net/publication/311194608_The_status_of_an_isolated_population_of_Goosander_Mergus_merganser_in_the_Balkans 

Catsadorakis, G., O. Onmus, S. Bugariu, O. Gül, D. Hatzilacou, O. Hatzofe, M. Malakou, T. Michev, T. Naziridis, H. Nikolaou, A. Rudenko, D. Saveljic, S. Shumka, M. Sıkı, A.J. Crivelli. 2015. Current status of the Dalmatian pelican and the great white pelican populations of the Black Sea/Mediterranean flyway. Endangered Species Research Vol. 27: 119–130. Available online at: http://www.int-res.com/articles/esr2015/27/n027p119.pdf

Catsadorakis, G., Aleksi, P., Avramoski, O., Bino, T., Bojadzi, A., Rajanoski, Z., Fremuth, W., Kazoglou, Y., Koutseri, I., Logotheti, A., Malakou, M., Nikolaou, H., Nikolaou, L., Putilin, K., Shumka, S., Uzunova, D. & M. Velevski. 2013. Waterbirds wintering at the Prespa Lakes as revealed by simultaneous counts in the three adjoining littoral states. Macedonian  Journal of Ecology and Environment. Vol: 15/ 1, p23-31. Available from: http://www.mjee.org.mk/pdf/Latest%20issue/Catsadorakis%20et%20al%202013-15-1.pdf 

Kazantzidis, S., G. Yfantis & K. Poirazidis 2013. Factors influencing species composition and nest abundance of heron colonies. Journal of biological Research-Thessaloniki 20: 276-289. https://www.academia.edu/22356138/Factors_influencing_species_composition_and_nest_abundance_of_heron_colonies 

Catsadorakis, G., Voslamber, B. & A. Logotheti. 2012. First Greylag Geese Anser anser rubrirostris ringed in Greece. Goose Bulletin, Issue 15, November 2012, pp. 28-31. https://www.academia.edu/31490497/First_Greylag_Geese_Anser_anser_rubrirostris_ringed_in_Greece 

Guidance on waterbird monitoring methodology: Field Protocol for waterbird counting Report prepared by Wetlands International March 2010. https://europe.wetlands.org/wp-content/uploads/sites/3/2016/08/Protocol_for_waterbird_counting_En_.pdf  

Catsadorakis, G. & A.J. Crivelli 2001. Nesting habitat characteristics and breeding performance of Dalmatian Pelicans in lake Mikri Prespa, NW Greece. Waterbirds 24:386–393. https://www.academia.edu/22441753/Nesting_Habitat_Characteristics_and_Breeding_Performance_of_Dalmatian_Pelicans_in_Lake_Mikri_Prespa_NW_Greece 

Crivelli, AJ, D. Hatzilacou & G. Catsadorakis 1998. The breeding biology of the Dalmatian pelican Pelecanus crispus. Ibis 140:472–481. https://www.academia.edu/31490486/The_breeding_biology_of_the_Dalmatian_Pelican_Pelecanus_crispus 

Catsadorakis, G. 1997. The importance of Prespa National Park for breeding and wintering birds. Hydrobiologia 351: 157-174. https://www.academia.edu/31490494/The_importance_of_Prespa_National_Park_for_breeding_and_wintering_birds