Red Knot
Scientific name: Calidris canutus
Family scolopacidae
- Phenology Mainland
- Wintering and passage migrant
- Phenology Madeira
- Vagrant
- Phenology Azores
- Vagrant
- IUCN Global Status
- Mainland Conservation Status
- Madeira Conservation Status
- Azores Conservation Status
Data
Presentation
Distribution, movements and phenology
The Red Knot breeds in the high Arctic between June and early August, wintering along the coastlines of all continents in both hemispheres (Billerman et al. 2026). Birds occurring in Portugal during migration mainly breed in the Siberian Arctic and winter primarily along the coasts of Africa (Delany et al. 2009). Birds from Greenland and Canada are also found in Portugal (Catry et al. 2010a). The main wintering areas are located almost exclusively in estuaries and coastal lagoons (Equipa Atlas 2018). On the rocky coast, the species is rare and has a localised distribution, appearing either singly or in small flocks. In the Azores and Madeira, the species occurs as a vagrant, and is observed mainly along the coastlines of the islands in these archipelagos.
Abundance and population trends
The global population has been estimated at between 750,000 and 1,750,000 mature individuals, with a declining trend (BirdLife International 2025). In Portugal, the abundance of the Red Knot is variable, ranging from tens to a few hundred individuals in winter (Catry et al. 2010a). The wintering population along the marine coast was estimated at only 17 to 18 individuals (Lecoq et al. 2013). The populations on the Mainland and in the Azores did not achieve Good Environmental Status for the abundance indicator. It was not possible to carry out this assessment for Madeira.
Ecology and habitat
In Portugal, Red Knots prefer wetlands, both coastal and inland, over the marine coastline. They are specialised predators of molluscs, including bivalves, which they capture mainly in soft sediments (Moreira 1994; Lourenço 2019). Nothing is known about the diet of the few birds that winter on our beaches.
Threats and conservation
The Red Knot is classified globally as Near Threatened, due to rapid declines observed in several populations. Among the main threats are habitat loss or degradation due to human activity, climate change affecting productivity, over-exploitation of bivalves and human disturbance (BirdLife International 2025). In Portugal, it may be particularly affected by the abandonment or degradation of salt pans, the conversion of salt pans into marine aquaculture facilities, and the destruction or degradation of intertidal zones.
Autor
Nuno Oliveira
Moreira F (1994). Diet and feeding rates of knots Calidris canutus in the Tagus estuary (Portugal). Ardea 82: 133-136. Bibliografia:
Lourenço PM (2019). Internet photography forums as sources of avian dietary data: bird diets in Continental Portugal. Airo 26:3-26. Bibliografia:
Lecoq M, Lourenço PM, Catry P, Andrade J & Granadeiro JP (2013). Wintering waders on the Portuguese mainland non-estuarine coast: results of the 2009-2011 survey. Wader Study Group Bulletin 120: 66-70. Bibliografia:
Equipa Atlas (2018). Atlas das Aves Invernantes e Migradoras de Portugal 2011-2013. Sociedade Portuguesa para o Estudo das Aves, LabOr- Laboratório de Ornitologia – ICAAM - Universidade de Évora, Instituto da Conservação da Natureza e das Florestas, Instituto das Florestas e Conservação da Natureza (Madeira), Secretaria Regional da Energia, Ambiente e Turismo (Açores) e Associação Portuguesa de Anilhadores de Aves. Lisboa. Bibliografia:
Delany S, Dodman T, Stroud D & Scott D (2009). An atlas of wader population in Africa and western Eurasia. Wetlands International, Wageningen. Bibliografia:
BirdLife International (2025). IUCN Red List for birds. Downloaded from https://datazone.birdlife.org on 30.11.2025. Bibliografia:
Billerman SM, Keeney BL, Kirwan GM, Medrano F, Sly ND & Smith MG (eds.) (2026). Birds of the World. Cornell Laboratory of Ornithology, Ithaca, NY, USA. Bibliografia:
Catry P, Costa H, Elias G & Matias R (2010a). Aves de Portugal, Ornitologia do Território Continental. Assírio e Alvim, Lisboa Glossário:
Individuals capable of breeding, used as a reference in population estimates. Glossário:
Molluscs with two shells, such as clams and cockles, common in intertidal environments. Glossário:
The coastal area that is exposed at low tide and submerged at high tide. Glossário:
Persistent changes in global or regional climate patterns, influenced by natural and anthropogenic factors. Glossário:
Areas where birds remain outside the breeding season, generally associated with favourable conditions for feeding and survival. Glossário:
A species or parameter that reflects the state of an ecosystem or environmental changes. Glossário:
The direction of change in the size of a population over time (increase, decline or stability). Glossário:
A measure of a population’s breeding success, generally expressed as the average number of chicks produced per pair. Glossário:
A concept defined under the Marine Strategy Framework Directive (MSFD), referring to the condition of the elements of the marine environment, including birds. It aims to assess whether ecosystems are healthy, balanced and capable of supporting ecological functions and human uses in a sustainable manner. The ultimate goal is for the components and ecosystems to achieve Good Environmental Status.
