[5] There are over 250 islands on the lake, and the lakebed is rocky, making navigation difficult but creating a good habitat for fish.

[6] While much of the lake is in the Canadian Shield, its southern portion is in the boreal forest where the Mercer River brings nutrients which leads to healthy invertebrate populations that provide plenty of food for the fish which are the mainstay of the eagles' diet.

Compared to the nearby and similarly sized Nemeiben Lake, which is entirely on the shield, the eagle population has a higher density and stability.

[3] The bald eagle community at Besnard Lake has been studied continuously for over 50 years following their discovery there by Jon Gerrard.

Besnard Lake was found to be a perfect area to study bald eagles in these boreal breeding grounds.

[3] One discovery was that the sex of immature eagles could be accurately and efficiently determined by measuring the size of the foot and length of the culmen on the beak.