By Sally Westwood
The Cormorant has a distinctive flight outline. Their body is narrow and linear, with outstretched wings. A Cormorant glided past me along the course of the River Deben, descending down to the surface of the water, staring ahead. The bird’s feet, webbed between four toes landed on the water, on stretched out, short legs. Water splashing loudly on impact. The feet touched the water at the base, or heel of the legs, with the rest of the foot held upright, to act as a break to landing. Using their feet like water skis. The extended, raised wings also slowed down the landing, gradually closing as the bird completely crashed on the water.
There are over 40 species of the Cormorant worldwide1. The Cormorant species usually present on the Deben, is the Great Cormorant Phalacrocorax carbo, (as shown in the image above). There are 9,018 breeding pairs of Great Cormorants in the UK and 41,000 birds overwinter here, in the coldest months of January and February2. The amount of overwintering Cormorants has been increasing annually since 1984, when laws were introduced to protect birds in Europe. Wintering birds then gradually extended their winter range into the UK. Another similar UK species to the Cormorant is the Shag, which is a marine species that is more likely to be present out at sea3. The Cormorant is also present in coastal areas. It has a lifespan of about eleven years. An adult can weigh between 2-2.5kgs. The wingspan is large, measuring between 130-160cms and the bird’s total length can range somewhere between 80-100cms.
The Cormorant appears to be a large conspicuous black bird, but I suspect they are not really noticed that often because of their habit of fishing under water. It has a scaly, primitive appearance with a long neck, that makes it more reminiscent of a reptile than a waterbird4. The Cormorant has a black body and when in breeding plumage it shows a white spot on the lower part of the body. The juvenile is white below and dark brown above5. Males and females have a similar plumage, but the male has a slightly large bill6. The wings show what can be thought of as brown scales, which are shiny when the bird is drying its wings out, with wings fully extended. The wings look ‘purplish’7 in bright sunlight. Since their wings are not waterproof they have to frequently dry them off8.
Cormorants fish in the brackish water of the Deben, as well as fresh and marine water9. They eat fish and eels which they catch whilst underwater, with a long, hook-tipped beak10. By contrast, there are other species of Cormorants, like the Double-crested Cormorant in America that uses boats as fishing perches11. Sadly, we are unlikely to see that species fishing in the River Deben. Cormorants do not always catch their prey. Great White Egrets have been seen wading in the Cormorants’ wake, in Norfolk, sinking their bills and necks deep below the water catching fish that have escaped from the Cormorant12. Freezing temperatures in winter months limits the availability of water for fishing13. Whereas, changes in temperature with warmer waters is advantageous for the species. It is thought Cormorants may mistake fragments of plastic for prey, which might block or perforate the digestive tract14. Birds commonly accumulate plastic in their stomachs and may later die of starvation, since it provides no nutrition for the bird. Interestingly, the Cormorant seems to be different. Cormorants have the ability to regurgitate plastic matter in pellets15. The Cormorant frequently emerges from the water near anglers because they are excellent fishers and are aware of the presence of fish, attracted to fishing baits16.They were persecuted in the past because of their fishing skills. They also had low breeding success in the 1950s and 1960s as a result of pesticide pollution17.
When there are high levels of food available, Cormorants are more likely to come into breeding at an earlier age than the usual age of sexual maturity which is between two to three years of age. Cormorants are able to usurp a sparse habitat and destroy existing vegetation with their nesting habits18, when they create a communal colony in one or more trees. Cormorants have only been found nesting in trees since 198119, not too far away from the Deben estuary, at Abberton Reservoir, Essex20. Prior to that time Cormorants were all coastal breeders. Tree branches are broken and used as nesting material, along with seaweed and weeds21. Constant droppings on trees, eventually kills the trees. Several solitary dead trees are present near the Wilford Bridge at Melton that are frequented by Cormorants. They used to be roosting sites, but now the birds only seem to use them for perching. The Inland Cormorants, such as those on the Deben have a longer breeding period than coastal Cormorants. The longer breeding period reduces the competition for food when the chicks are large. Whereas, coastal birds hatch chicks all at the same time, increasing competition for food22. Perhaps not surprisingly, coastal Cormorants have been declining since 198623.
Like most of the birds near or on the Deben, the Cormorant is protected by The Wildlife and Countryside Act 198124. The Cormorant is of ‘least concern’ on the Red List of endangered birds, and the trend for the species is ‘increasing’25.
Sally Westwood
Sally Westwood is a Psychologist, and works as a researcher. She has taught in higher education as an English Language teacher. Her interests are varied. She has written many articles for Bird Magazines and Journals. She is also a professional bird photographer. Birds are her passion. She loves to draw and paint birds. She lives on a boat on the Deben and loves to sit and be with the birds, simply watching and photographing birds, in their daily activities.
Footnotes
1 Sibley, D., A., (2001) The Sibley guide to bird life and behaviour. London: Chanticleer Press Inc.
2 Birdspot. (2022) What do cormorants look like. Available from: https://www.birdspot.co.uk/bird-identification/cormorant [Retrieved 28 October 2022].
3 Acampora, H., Berrow, S., & Newton, S., (2017) Presence of plastic litter in pellets from Great Cormorant (Phalacrocorax carbo) in Ireland. Marine Pollution Bulletin. 117, 1-2, 512-514.
4 RSPB. (2022) Cormorant. Available from: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/cormorant/ [Retrieved 26 October 2022].
5 Wildlife Trusts. (2022) Cormorant. Available from: https://www.wildlifetrusts.org/wildlife-explorer/birds/seabirds/cormorant [Retrieved 28 October 2022].
6 Birdspot. (2022). As above.
7 Selous, F., C., & Nelson, T., H., (2017) On the Europeans form of the Cormorant and Little Bustard. British Birds, 10, 9, 210-214.
8 Wildlife Trusts. (2022) As above.
9 Birdspot. (2022). As above.
10 Wildlife Trusts. (2022) As above.
11 Titlow, B., (2022) Double-crested cormorants use boats as fishing tools. Available from: https://eu.tallahassee.com/story/life/home-garden/2014/06/26/double-crested-cormorants-use-boats-fishing-tools/11407245/ [Retrieved 28 October 2022].
12 Bloomfield, A., & Scampion, B., (2017) Interactions between Great White Egrets, Grey Herons, and Cormorants at Holkham, Norfolk in October 2016. British Birds, 110, 675-684.
13 Van Eerden, M., van Rijn, S., & Valponi, S., (2012) Cormorants and the European Environment: exploring Cormorant status and distribution on a continental scale. Intercafe Cost Action 635 Final Report.
14 Acampora et al., 2017). As above.
15 Acampora et al., 2017). As above.
16 RSPB. (2022). As above.
17 BTO. (2022) Identifying birds. Available from: https://www.bto.org/understanding-birds/species-focus/cormorant [Retrieved 28 October 2022].
18 Giammaring, M., Quatto, P., & Renna, M., (2021) Impacts of Great Cormorant and Cattle Egret Nesting on Other Waterbirds in a Shared Breeding Site in Piedmont (NW Italy). Acta Ornithologica, 56, 1, 39-50.
19 BTO. (2022). As above.
20 Newson, S., Marchant, J., & Sellers, R., (2013) Colonisation and range expansion of inland-breeding Cormorants in England. British Birds, 106, 737-743.
21 BTO. (2022). As above.
22 BTO. (2022). As above.
23 BTO. (2022). As above.
24 RSPB. (2022). As above.
25 BTO. (2022). As above.
