How the use of DDT affected the Peregrine Falcon (Falco peregrinus) in Great Britain

Peregrine Falcon

After the Second World War, 1945, having successfully fought for their country soldiers were reunited with their families would have to find a new means of work. These practical men would need to provide for their families and earn money once again. The ever expanding population would lead to a high requirement of food stuffs; this demand resulted in  a constant trade as food will always be required. The main aim in food production is to achieve the highest yield and create the greatest profit.  To do this a control method must be in place to stop pests reducing yield.  

Peregrine Falcon. Pixabay.

Our native species are the flora and fauna that were in England before the sea was formed between England and France around 7,500 years ago. When looking at species abundance, there is an average of 40 species known as native to Britain, every other one has been introduced. It is found (POST, 2008) that these invasive non-native species can and have posed many threats to our low abundance of native species of both flora and fauna. Bird and Seal species are called native if they are known to breed in Britain, there have been many habitats found along our coast line but cannot be classified as native species of Great Britain, for example dolphins and porpoises.  Many common species were introduced to Britain, like the rabbit purposefully as a food source and rats accidentally coming over on cargo ships. We have 60 species of mammal present in Britain, 18 of them are non-native. The climate continuously changing allows foreign species to spread to areas that before were unavailable to them, (Wildlife Britain, 2007). Over the last few years it has become apparent that the climate change of the world is changing the distribution of Britain’s species and their habitats (Buckland and Elston, 1993). It is known (Yalden, 2012) that another reason for the reduced number of native species is hunting many years ago and more recently, farming.  

Throughout time there has been a use of many different methods to control pests and unwanted weeds. This had led to a leaching of nitrogen into the water supply which destroys wildlife that lives in the water as well as land mammals and birds of prey (Kish and Martin, 2006). It affects all these animals by moving up through the food chain, from the fish swimming in contaminated waters, to the birds that feed on the fish.  This can result  in many species becoming endangered and extinct. Many species have however been reintroduced, for example the otter, peregrine falcon (Falco peregrinus) and many species of butterfly, (Yalden, 2012). 

Peregrine Falcon. Pixabay.

Natural England carries out a lot of projects towards conserving the animals that have been re-introduced. In England a huge number of species have been lost over the recent 200 years, including 12% of land mammals (Act for Wildlife, no date). It is known from work done by ornithologist, Robert Robinson that there are roughly 110 birds in the Britain isles of “conservation concern”. Nonetheless, Harrison (2010) says there are species that have flourished for example the Red Kite which has about 1,000 breeding pairs and there are many legal acts that help protect many other species.  

There are many types of control in place regarding the prevention of crop depletion including many variations of pesticides. Organochlorine pesticides and insecticides were introduced in the 1950s, the most well known and strongest one being dichlorodiphenyltrichloroethane (DDT), which was first used in the Second World War to prevent the effect of many infectious diseases on soldiers. In (date) Swiss physicist, Paul Muller found in 1942 that DDT was a highly effective pesticide, (Harrison, 1996/7). It is this same chemical that is responsible for the thinning of egg shells therefore leading to near extinction of the osprey, peregrine falcon and many water fowl (The Nobel Foundation, 1948). Even though DDT has been banned since the 1970’s it has the half life of around 15 years, (U.S Environmental Protection Agency, 2011). However, depending on the environment and the soil, water type or mammal it has infected the half life could vary, from 28 days up to, realistically, 20 years, (John, 1999/2001). 

Peregrine Falcon (Falco peregrinus) Pixabay

DDT was designed as a chemical that cannot be destroyed, as the petrochemical era evolved this chemical it was originally sprayed onto humans as a use of defence against malaria and throughout time it was continuously used on crops says Muir (2007). There was then a pandemic of cancer spread throughout the areas sprayed and it infected those who ate the plants, those who have created a habitat in the planted area and thus resulting in many birth defects in humans, animals and the Peregrine Falcons. The strong chemical pesticides were soon stopped because of the impact they had on not only these birds but the overall environment. Many food chains became poisoned, including the Otter’s – it seemed to affect their immunity making them more susceptible to disease. Until now the otters were wide spread throughout Great Britain, however such charities like the Otter Trust based in Suffolk have recreated chemical free habitats resulting in successful areas where they are protected and offspring can thrive. In 1978 the otter was given legal protection as it had totally vanished in certain areas, they can now however be found in Cumbria and many places in East Anglia. 

There were a high variety of birds of prey species that declined due to the use of many pesticides, however it was DDT that affected almost all birds of prey including the peregrine falcon . It is known that the insecticide reduces the amount of calcium carbonate being transferred to the egg shell (Walker et al, 2006). Biomagnification of this organochlorine pesticide begins to build up in the bird’s fatty tissue as it is a fat soluble chemical, resulting in a reduced concentration of calcium carbonate in the egg shell, making it weak and reducing the abundance of chicks hatched. (Ratcliffe, 2009). A review from Ferns et al. (2008) states that the affected egg will show many different aesthetical signs, including the shade of the egg and spots on the shell. The fact that birds of prey are becoming contaminated shows that the problem is quite wide spread as they have a large territory upon where they feed. The Peregrine Falcon now has an estimated 1402 breeding pairs throughout Britain, RSPB (2011). This is proof that reintroduction and protection acts and programmes can successfully increase the biodiversity in Great Britain.  

Peregrine Falcon (Falco peregrinus) Pixabay

The Wildlife and Countryside Act 1981 has given full protection to the Peregrine Falcons, their eggs and their nests, making it a crime to come into contact physically or being held responsible for any damage to their habitat and ecosystem (Joint Nature Conservation Committee, 1981). There are many levels of protection within the Act, the peregrine falcon is in schedule 1, which is the highest, resulting in the highest penalty if any one were to be prosecuted (London Peregrine Partnership, 2012). There are many groups throughout the United Kingdom that run programmes to protect the breeding areas of these predatory birds, including the Forest of Bowland, an area not only of Outstanding National Beauty but also where their largest breeding bird is the Peregrine Falcon (Forest of Bowland, 2012). They have put together information about breeding attempts within the Forest for the last 34 years.  They currently have around 22.5 breeding pairs, with a total of 113 successful broods and 241 young from 320 nesting attempts, working out at 2.13 offspring per successful nest. With success comes failure – there were a number of unhatched eggs and chicks who didn’t leave the nest (Raptor Politics, 2012). Furthermore, it is the dedication from members of organisations who together are responsible for the ever rising numbers of Peregrine Falcons.   

The London Wildlife Trust is a charity that carries out numerous types of conservation methods and has built up a large range of partnerships that enables them to have a large impact on as many projects with a wide variety of biodiversity. For over 30 years they have worked with organizations such as Defra and Natural England to produce an array of environmental schemes including the protection of falcon nests, (Forest of Bowland, 2012). Now the ban on DDT has been in place about 40 years the main threat to these reintroduced birds is another farming impact. The principle with farming is still the same, to produce a high yield and create the most profit, however in order to do this larger crop fields are needed, reducing the land and habitats around and therefore reducing the biodiversity by removing hedgerows, ponds and woodland areas.  

Peregrine Falcon (Falco peregrinus) Pixabay

The Sussex Peregrine Study founded by John Franklin is a group of raptor specialists who work together to not only create a summary of Peregrine numbers within the UK but also to educate others about this magnificent bird and construct relationships with other specialists, like their partners the London Peregrine Partnership. Franklin, (2010) states they currently have successful nesting sites throughout Sussex and have continued to grow since the first protected one created in 1990. It is groups of people like these men who are reliable for the ever increasing numbers.  

Throughout the most recent years many areas have become protected and there are areas that will keep expanding for the nesting of these remarkable birds. They are important, as are most animals that help create a larger biodiversity within the shore of Great Britain. The farming industry is continuously expanding but with the combination of education and grants being widely available to farmers throughout England our wildlife, and especially peregrine falcon numbers should keep rising. Defra offers grants to farmers who keep wildlife corridors, hedgerows and set-aside fields to harbour wildlife.  They also review programmes regularly such as the recent Habitats and Wild Birds Directives in November 2011 where they look at the current projects and analyse whether they are being conducted to their full potential. (DEFRA, 2011). These reviews are required because it keeps the initial purpose in focus and that all requirements are filled within the environment.  

Overall it is proved that the conservation techniques in place are helping with the rising of peregrine falcon numbers in Great Britain. The ban of DDT in early 1970’s was the first step towards this escalation, even if it had been used continuously in the agricultural industry for consecutive 20 years. Technology has advanced and produced many different alternatives for crop protection, for example organic pesticides and a new organic farming methods have been thrust upon modern day farmers. Defra plays a key part in promoting this style of farming, paying farmers who choose this scheme, also, the public are becoming more informed with the use of media that they choose for their family organically grown produce, (Organic Farming, no date). The media can portray certain subjects in whatever way necessary, good or bad, right or wrong. It is known DDT causes bad effects on the ecosystem and humans therefore a medium can be produced to promote the farmers who use environmentally friendly control methods. A conclusion that can be made is that there is a high requirement for people to have an interest in the protection of species within the UK, and creating areas for these species to thrive. The Peregrine Falcon is one of many species that because of a reintroduction programme is starting to thrive within the shores of the United Kingdom. 


Act for Wildlife (no date) UK Wildlife Conservation. Available at: (Accessed: 3 January 2012). 

Buckland, S.T. and Elston, D.A. (1993) ‘Empirical models for the spatial distribution of wildlife’, Journal of Applied Ecology, 30(3), pp. 478-495.  

Department for Environment Food and Rural Affairs (DEFRA) (2011) Habitats and Wild Birds Directive- review of implementation. Available at: (Accessed: 3 January 2012). 

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Harrison, K. (1996/7) ‘DDT a Banned Insecticide’, University of Oxford, Department of Chemistry. [Online]. Available at: (Accessed: 3 January 2012). 

John, C. H. (1999/2001) ‘Half-Life of DDT’, Ask a Scientist. [Online]. Available at: (Accessed: 3 January 2012). 

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Kish, S. and Martin, J. (Apr, 2006) ‘Organic and Integrated Farming Key to Lowering Nitrogen Leaching’, National Institute for Food and Agriculture, [Online]. Available at: (Accessed: 3 January 2012).  

London Peregrine Partnership (2012) Peregrine Falcons and the Law. Available at: (Accessed: 3 January 2012). 

Muir, P. (2007) A History of Pesticide. Available at: (Accessed: 5 December 2011). 

Raptor Politics (2012) Historical and Statistical Data of Peregrine Falcons and Hen Harriers, Lancashire. Available at: (Accessed: 3 January 2012). 

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U.S Environmental Protection Agency (2011) ‘DDT’, Persistent Bioaccumulative and Toxic (PBT) Chemical Program. [Online]. Available at: (Accessed: 5 December 2011). 

Walker, C.H., et al (2006) Principles of Ecotoxicology. 3rd edn. Boca Raton, CRC Press.   

Wildlife and Countryside Act (1981) Part 1 Wildlife, protection of wild birds their nests and eggs. Available at: (Accessed: 3 January 2012).  

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Yalden, D.W. (2012) A History of British Mammals. The Mammal Society. Available at: (Accessed: 3 January 2012).  


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