APODIFORMES: Apodidae
Apus pacificus
Fork-tailed Swifts are Summer migrants from the northern hemisphere.
Their appearance wheeling about the sky is often an indicator of coming rain. This was one of two or three Fork-tailed Swifts observed on an overcast day. There were a few spits shortly after and a lot more rain the next day.
One wonders what these birds are doing when the weather is fine.