Final answer:
The food chain of ospreys and northern harriers differ in terms of their diet, with ospreys primarily feeding on fish and northern harriers feeding on small mammals. This difference can result in different amounts of DDT in the birds' systems, as DDT can accumulate and biomagnify through the food chain.
Step-by-step explanation:
The food chain of ospreys and northern harriers differ in terms of their primary prey. Ospreys primarily feed on fish, while northern harriers feed on small mammals. These differences in diet can result in different amounts of DDT in the birds' systems. DDT is a pesticide that can biomagnify through the food chain. When birds consume prey that has accumulated DDT, the chemical can build up in their bodies, potentially affecting their reproduction. For example, populations of bird species at the top of the food chain, like eagles and pelicans, were greatly affected by DDT because their eggs became too thin to survive.
Ospreys feed mainly on fish and are at greater risk of DDT accumulation due to biomagnification in aquatic ecosystems. Northern harriers feed on a variety of prey, including small mammals, and might accumulate less DDT. The difference in diets impacts the levels of DDT in these birds.
Differences in the Food Chains of Ospreys and Northern Harriers
The primary difference between the food chain of ospreys and that of northern harriers relates to their main sources of food. Ospreys predominantly feed on fish, making their diet mainly aquatic, while northern harriers have a broader diet that includes small mammals among other prey. Regarding the impact of DDT, because ospreys primarily feed on fish, they are more directly affected by this pesticide, which tends to biomagnify in aquatic ecosystems. Biomagnification leads to higher concentrations of DDT in apex predators like ospreys.
DDT is especially problematic for bird species at the top of the food chain, as it leads to the thinning of eggshells, causing them to break and significantly affecting bird reproduction rates. Consequently, differences in diets between ospreys and northern harriers could result in different levels of DDT accumulation, with ospreys likely ingesting higher levels due to their fish-based diet. Northern harriers, with a more varied diet, might accumulate less DDT, provided their prey sources are less affected by this pesticide.