The slender-billed grackle was originally known from the Rio Lerma area in Mexico. It has not been recorded since 1910. Several records of the slender-billed grackle are known from three different habitats, such as wetlands, cultivated plots, and human settlements. Slender-billed grackles inhabited marshes and borders of the lakes. Emergent aquatic vegetation was commonly used for nesting material by the slender-billed grackles.
