Sixteen lovebirds have been taken from an aviary in Backwell.
The theft follows a similar incident in Weston-super-Mare on 25 February when two African Grey Parrots and nine lovebirds were stolen.
Pete Rollings, who owns the Backwell aviary, said he believed whoever took his lovebirds knew exactly what they were looking for.
He is urging fellow bird owners to check their security and to contact police if they are offered the birds.