Saw these little birds at the beach today. Thought they were one thing, but a search eventually told me they are New Zealand dotterels. One photo has an Oystercatcher to show the relative sizes.

Small bird with pale and russet belly, darker back, stout black bill.
Side view of small bird with pale and russet belly, darker back, stout black bill.
Small bird next to much larger black bird.
Miraz Jordan @Miraz