On 27 October, during the landings at the Treasury Islands by New Zealand infantry and supporting troops, the squadron flew covering missions throughout the day. In doing so, they intercepted a force of 80 Japanese aircraft attempting to attack barges landing supplies and shot down four fighters, with Herrick accounting for one of them, a Zero. The squadron also flew missions protecting the beachhead on Bougainville throughout November. On one of these missions, Herrick was wounded in the foot during an attack on Japanese defensive positions. This would be his final sortie for he handed over command of the squadron and left to return to New Zealand. In recognition of his services in the Solomons, Herrick was awarded a bar to his DFC; this was gazetted in February 1944.