Red Squirrels (Sciurus vulgaris):
* More Specialist: Red squirrels are considered more specialist in their ecological niche.
* Diet: They primarily rely on conifer seeds (especially pine and spruce) for food. While they will eat other things, their dependence on conifer seeds makes them more vulnerable to fluctuations in seed availability.
* Habitat: They prefer mature coniferous forests and are less adaptable to a wider range of habitats compared to grey squirrels.
* Competition: They are less competitive with other species, particularly the invasive grey squirrel.
Grey Squirrels (Sciurus carolinensis):
* More Generalist: Grey squirrels are considered more generalist.
* Diet: They have a wider and more flexible diet, consuming a range of nuts, fruits, seeds, and even insects. This gives them a greater ability to find food in different environments.
* Habitat: They are adaptable to a wider range of habitats, including deciduous forests, parks, and even urban areas.
* Competition: They are more competitive, often outcompeting red squirrels for resources.
Key Considerations:
* Invasive Species: The grey squirrel is an invasive species in many parts of Europe, where it displaces the native red squirrel. This highlights the competitive advantage of generalists in new environments.
* Adaptability: Generalists are better equipped to handle changes in their environment, making them more resilient in the face of human-induced habitat alterations.
In conclusion: Red squirrels are more specialized, while grey squirrels are more generalist. This explains why grey squirrels have been so successful in expanding their range and outcompeting red squirrels in many areas.