Assertion: nightjar's egg | /r/HasProperty | incubated by the female
Facets:
value: alone
type: MANNER
value: for about 20 days
type: TEMPORAL
Source sentences:
text: In a concealed spot on the ground, two eggs are laid and incubated by the female for about 20 days.
text: The breeding season varies according to the climate; the eggs often but one, rarely three in number, are incubated by the female alone.