Final answer:
The songbird species is best described by a Type II survivorship curve, where there is an equal chance of death at any age throughout the bird's life.
Step-by-step explanation:
The idealized survivorship curve being described for a songbird species with a constant chance of death throughout its lifespan is Type II survivorship curve.
Survivorship curves are used by ecologists to illustrate the life span patterns of different species by plotting the number of individuals surviving at each age interval. The Type II curve represents species where mortality rates do not vary significantly with age, which means the chance of death is roughly equal at any age.
This is typical of many bird species as they face a consistent level of predation, environmental challenges, and diseases throughout their lives, unlike humans and other mammals that show a Type I curve where mortality is higher in old age, or trees and some invertebrates that exhibit a Type III curve where mortality is highest in early life stages but much lower for individuals who live to an older age.