Use the Diagram Showing the Spread of the Cattle Egret

Multiple Choice

Use the diagram showing the spread of the cattle egret, Bubulcus ibis, since its arrival in the New World, to answer the question.

The range of cattle egrets has expanded between 1937 and today. How would an ecologist likely best explain the expansion of the cattle egret?

A) Climatic factors, such as sunlight, temperature, and precipitation, provide a suitable habitat for cattle egrets.
B) There are no predators for cattle egrets in the New World, so they continue to expand their range.
C) The abundant area and little competition with other birds occupying similar habitats met the biotic and abiotic requirements of the cattle egret expansion.
D) The first egrets to colonize South America evolved into a new species capable of competing with the native species of herons and egrets.