Mondego Estuary
International Waterbird Census
Since 1994, counting to
better monitor aquatic birds
how many waterbirds?
Here we show the results of the waterbird counts made at the peak of Winter (January) since 1994. It is the result of the voluntary effort of several researchers during 27 years, making this the longest non-interrupted time series of the total abundance of waterbirds in a Portuguese estuary, using the same methodology.
You can hide a species by clicking in their name, in the legend. Ultimately you can see a single species by deselecting all the others.
what is the IWC?
The IWC (International Waterbird Census) is a monitoring programme operating in 143 countries to collect information on the numbers of waterbirds at wetland sites. It requires a single count at each site, which should be repeated every year. The precise dates vary slightly from region to region but take place in January or February. In the Africa-Eurasia regional scheme, where Portuguese wetlands are located, they take place in January.
what species are counted under the IWC?
All types of waterbirds regularly encountered at wetlands: grebes, cormorants, pelicans, herons, egrets, storks, ibises, spoonbills, flamingos, ducks, geese, swans, cranes, rails, jacanas, shorebirds, gulls, terns and skimmers. In addition raptors, kingfishers and other birds largely dependent on food resources in these habitats are often reported.
In this gallery are shown many of the species that were already photographed during the Mondego IWC monitoring.
public data, counted by volunteers
Many thousands of volunteers join the IWC every year, making it one of the largest citizen science programmes in the world. In the Mondego Estuary, there were irregular counts since the ’80s. However, the standardized regular January counts in the Mondego Estuary started in 1994 by Tiago Múrias Santos and João Alexandre Cabral for their post-graduation thesis. Ricardo Jorge Lopes joined in 1995 and after the end of his PhD thesis in 2004 continued to run the census to this day.
Many people helped on the census, especially Tiago Múrias Santos, Paulo Tenreiro and Luis Silva. Many other volunteers joined, including Carlos Pacheco, Patricia Pedro, Jaime Ramos, David Monticelli, João Pedro Neves and we are probably missing someone!
data for local conservation
The data from the Mondego IWC has been critical for the identification and the designation of the Mondego Estuary as an important site for biodiversity at the international level.

The Mondego Estuary was designated in 2005 as an Important Bird and Biodiversity Area by the BirdLife International and SPEA, using the IWC data. See more information.

The Mondego Estuary was designated in 2006 as a Ramsar Site (Wetland of International Importance) using mostly data from the Mondego IWC.
data for science
The data from the Mondego IWC has been important to understand the importance of the Mondego Estuary and as a case study to address many important scientific questions. Here we show some of the outputs that used the Mondego IWC data.
- Múrias T, Cabral JC, Marques JC, Goss-Custard JD (1996) Short-term Effects of Intertidal Macroalgal Blooms on the Macrohabitat Selection and Feeding Behaviour of Wading Birds in the Mondego Estuary (West Portugal). Estuarine, Coastal and Shelf Science 43(6): 677-688.
- Múrias T, Cabral JC, Lopes RJ, Marques JC (1997) Low-water use of the Mondego Estuary (West Portugal) by waders (Charadrii). Ardeola 44(1): 79-91.
- Cabral JA, Múrias T, Lopes RJ, Marques JC (1996) Macroalgae blooms and macrohabitat selection by waders: a study in Mondego Estuary (Western Portugal). Airo 7: 1-6.
- Cabral JA, Pardal MA, Lopes RJ, Múrias T, Marques JC (1999) The impact of macroalgal blooms on the use of the intertidal area and feeding behaviour of waders (Charadrii) in the Mondego estuary (Portugal). Acta Oecologica 20(4): 417-427.
- Lopes RJ, Cabral JA, Múrias T, Pacheco C, Marques JC. Status and habitat use of waders in the Mondego estuary. In: Pardal MA, Marques JC, Graça MAS (eds) Aquatic ecology of the Mondego river basin. Global importance of local experience. Imprensa da Universidade de Coimbra, Coimbra. pp. 219-230.
- Múrias T, Cabral JA, Lopes RJ, Marques JC. Effects of eutrophication on waders (Aves, Charadrii) in the Mondego estuary: a multi-level approach. In: Pardal MA, Marques JC, Graça MAS (eds) Aquatic ecology of the Mondego river basin. Global importance of local experience. Imprensa da Universidade de Coimbra, Coimbra. pp. 527-540.
- Múrias T, Cabral JC, Lopes RJ, Marques JC, Goss-Custard J (2003) Use of traditional salines by waders in the Mondego estuary (Portugal): A conservation perspective. Ardeola (2003) 49(2): 223-240.
- Lopes RJ, Múrias T, Cabral JC, Marques JC (2005) A ten year study of variation, trends and seasonality of shorebird community in the Mondego Estuary, Portugal. Waterbirds 28(1): 8-18.
- Múrias T, Cabral JA, Lopes RJ, Pardal M, Marques JC, Goss-Custard (2005) Competition for feeding in waders: A case study in an estuary of south temperate Europe (Mondego, Portugal). Hydrobiologia 544: 155-166.
- Silva-Santos P, Pardal MA, Lopes RJ, Múrias T, Cabral JA (2006) A Stochastic Dynamic Methodology (SDM) to the modelling of trophic interactions, with a focus on estuarine eutrophication scenarios. Ecological Indicators 6: 394-408.
- Lopes RJ, Pardal MA, Múrias T, Cabral JA, Marques JC (2006) Influence of macroalgal mats on abundance and distribution of Dunlin Calidris alpina in estuaries: A long-term approach. Marine Ecology Progress Series 323: 11-20.
- Silva-Santos P, Pardal MA, Lopes RJ, Múrias T, Cabral JA (2008). Testing the Stochastic Dynamic Methodology (StDM) as a management tool in a shallow temperate estuary of south Europe (Mondego, Portugal). Ecological Modelling 210: 377-402.
- Silva-Santos P, Lopes RJ, Murias T, Medeiros J, Cardoso P, Dolbeth M, Pardal MA, Cabral JA. The use of stochastic models as a management tool in a shallow temperate estuary of south Europe (Mondego, Portugal). In: Pirog RS (ed) Seagrass: Ecology, Uses and Threats. Nova Science Publishers. pp. 157-175.
the Mondego Estuary, a special place
The estuary of the longest river exclusively in Portuguese territory is unique among the Portuguese estuaries due to the presence of a large alluvial island (Morraceira island). This isolation prevented the development of large industries and preserved a set of habitats, from intertidal mudflats to a well preserved set of artisanal saltpans. In this gallery are shown many of the habitats that makes this estuary an important site to conserve.
a special thanks for
During all this time we are indebted for the institutions that supported the Mondego IWC, either financially or by supporting the researcher’s activities.






