If walking outdoors is your kind of thing, you are likely to come across a couple of quero-queros (Southern Lapwing, Vanellus chilensis), a very common bird in South America outside the Amazon basin and the Andean region.
Quero-queros build their nests on the ground. If someone comes close to the nests, they defend them very aggresively. Quero-queros gave us a bit of a rough time at the Lençóis Maranhenses last year. We were unlucky enough to find ourselves strolling along a succession of quero-quero nests for more than an hour. During that time, we were mercilessly harrassed by the birds, having to duck the entire time to avoid being hit by their spurs. When we left the proximity of a nest in the belief we were now on safe ground, we would invariably enter the proximity of yet another nest, being the target of yet more low-level flights. It was quite an unpleasant experience although completely understandable.
If you ever come across a couple of quero-queros defending their nests, go away as far as you can. They mean business.