Like many plays at the Fringe, Nesting can’t decide what genre it wants to be. It has two dramatic stories: a woman facing the birth of her first child and her father confronting a terminal, degenerative illness, and slips between light comedy and tragedy. A seagull becomes a squawking symbol of death, offering some kind of possession of the dying man’s body, while the daughter alternates between worrying about the pregnancy and her father. It is an unsatisfactory confusion of themes and stories, well-performed and with nice observations of the medical process and domestic life but never quite resolving the various threads.

The strongest narrative is the father’s degeneration; when he realises the consequences of his illness, he meets the seagull who vacillates between friendliness and predatory bargaining. While there is an attempt to challenge the pressure placed on women within a family to support everyone, this feels under-developed and gestural. The seagull, however, is the most striking character: aggressive, cajoling and clear in its selfish intentions, it combines the swagger of a gangster with a cackling cynicism. Although it’s well-paced and has a solid cast, Nesting is a slight production that sketches out the medical drama without closing in on the telling detail or finding a theatrical climax.

Nesting, Summerhall, until 31 August, 4.30pm; picture: Alex Brenner.