The crested serpent eagle and the black-naped monarch are endemic subspecies of Taiwan and inhabit forests at low to medium elevations. The breeding season of the crested serpent eagle is from March to June. Each clutch contains 1 egg. The incubation period is about 35 days. After another 60 to 75 days, the young leave the nest. Nesting sites and materials are repeatedly used. The breeding season of the black-naped monarch, which mainly feeds on insects, is from April to July. There are usually 3 eggs per clutch and males and females jointly incubate the eggs and care for their young. About 13 to 14 days are needed for the eggs to hatch and another 10 days for the young to leave the nest. Their nesting grounds and breeding seasons often overlap. A pair of crested serpent eagles constructing a nest. When one returned to feed its young, it startled a black-naped monarch nesting nearby. The black-naped monarch flew around the eagle several times, and waved its claws, unafraid. For the sake of their young, both birds held their ground, demonstrating the bravery and resilience of mothers in nature.