Field Ant (Formica spp.)

Large Outdoor Ant • Common Near Stone Walls & Yards in CT

Field Ant – Connecticut Identification & Outdoor Behavior Guide

Field ants are common across Connecticut lawns, stone walls, walkways, and wooded edges. While they rarely nest inside homes, they are often mistaken for carpenter ants due to their size and outdoor activity. Field ants can form large mounds and may bite when disturbed.

Identification:

• Size: ¼–⅜ inch
• Color: Red, black, or red-and-black
• Waist: One node
• Behavior: Fast movers, often seen in large numbers
• Habitat: Outdoor nesting in soil and debris

These ants do not excavate wood, helping differentiate them from carpenter ants.

Behavior & Habitat:

Field ants build:

• Large soil mounds
• Nests under rocks
• Colonies along stone walls
• Mounds at tree bases

They feed on:

• Dead insects
• Honeydew from aphids
• Outdoor food sources

Why They Are Common in Connecticut:

CT landscapes provide ideal habitat:

• Stone walls
• Forest edges
• Moist soil
• Gardens
• Mulched beds

They often appear after rain or during warm seasons.

Signs of Field Ants:

• Large ant mounds in lawns
• Trails on patios
• Activity around stones
• Worker ants carrying soil

When to Call a Professional:

Treatment is recommended when mounds threaten lawns, patios, or become too close to the home.

Ant Control CT 

Additional Links:

• Carpenter Ant Page 
• Pest Prevention