How did European starlings become one of the most common birds in America?

The introduction of European starlings (Sturnus vulgaris) to America is an intriguing case study of an unexpected ecological success. The spread and dominance of this non-native species can be attributed to a combination of factors, including deliberate human introduction, adaptability, and ecological niche occupancy. Here's how European starlings became one of the most common birds in America:

1. Deliberate Introduction:

- In the late 1800s, Eugene Schieffelin, a Shakespeare enthusiast from New York City, sought to introduce every bird mentioned in the works of William Shakespeare to North America.

- Believing that starlings were referenced in Shakespeare's plays, Schieffelin imported and released 60 starlings in New York City's Central Park in 1890.

- This initial release marked the beginning of the European starlings' establishment in the United States.

2. Adaptability and Resourcefulness:

- European starlings are highly adaptable birds capable of thriving in diverse habitats.

- They are opportunistic omnivores, consuming a wide range of food sources, including insects, seeds, fruits, and human-provided scraps.

- Starlings are also cavity nesters, using tree hollows, eaves of buildings, and even holes in cars to construct their nests. This allowed them to find suitable nesting sites in both rural and urban environments.

3. Ecological Niche Occupancy:

- European starlings found a vacant ecological niche in North America, filling the role of medium-sized, cavity-nesting birds that forage on the ground.

- They faced limited competition from native species and quickly proliferated, exploiting this unoccupied ecological niche.

4. Rapid Population Growth:

- Starlings have a high reproductive rate, producing multiple broods per year.

- Each brood can consist of 4 to 6 eggs, and the hatchlings have a high survival rate.

- Their ability to reproduce quickly further facilitated their population expansion.

5. Lack of Natural Predators:

- European starlings did not face significant predation in their introduced environment, as many native predators were either absent or unable to adapt to their specific habits and behaviors.

- The absence of natural predators allowed their populations to grow unchecked.

6. Human Assistance:

- Human activities inadvertently aided the starlings' spread.

- The development of farms, cities, and other human-altered landscapes created new habitats suitable for starlings.

- Additionally, the availability of artificial food sources, such as bird feeders and garbage dumps, further supported their population growth.

As a result of these factors, European starlings quickly multiplied and dispersed across North America. They now inhabit a wide range of habitats, from open fields and woodlands to urban areas. Their success as an introduced species highlights their adaptability and the complexities of ecological interactions.