Built of uncoursed limestone rubble, this modest structure at Portanure is a dovecote, one of the quieter remnants of an agricultural and social order that expected landowners to keep a ready supply of fresh meat and eggs through the winter months. It survives to string-course level, the decorative horizontal moulding that would originally have marked a transition in the wall's elevation, and inside, six rows of rectangular nesting boxes are still visible, each a neat 22 centimetres high and wide, and 44 centimetres deep; small, precise chambers engineered for pigeons.

The structure is likely connected to a bawn that stands roughly 60 metres to the north-north-west. A bawn is a fortified enclosure, typically a walled courtyard attached to or surrounding a tower house or plantation-era residence, intended to protect livestock and provide a defensible perimeter. That associated bawn at Portanure dates to the late sixteenth or early seventeenth century, placing the dovecote squarely in the plantation period, when new English and Scottish settlers were establishing fortified households across Ireland. The dovecote's single doorway, a flat-headed opening just over a metre wide that was later rebuilt, faces directly towards the bawn wall, suggesting the two structures were conceived and used together as part of the same defended domestic complex. The tower's internal diameter of just over three metres and its walls three-quarters of a metre thick give it a solidity that seems almost excessive for a pigeon house, though the limestone rubble construction was practical and the thickness would have helped regulate the temperature inside.