|Martin eggs are white. Sparrow eggs are brown speckled and their nests fill the entire space. Martin nests are a "carpet" of leaves, grass and small sticks.|
We have four Purple Martin houses, each with 12 "apartments." I look in the houses at least once a week to make sure sparrows have not built nests in them. If they do, I pull them out, Sparrows are invasive and will kill babies and adults. They also will peck the eggs or push them out. They do this to martins, bluebirds, catbirds, wrens, robins and cardinals, at least.). Here is what's growing in some of the apartments.