听力音频：
L1
讲座
1. What is the lecture mainly about?
Recent research on the development of contact calls in wild psittacines
The nesting behaviors of different psittacine species
A study comparing the contact calls of domestic and wild psittacines
The genetic basis of birdsong development in a wild psittacine species
2. According to the discussion, why are psittacines in the wild usually difficult to study?（多选题）
Male and female psittacines appear nearly identical.
Most species can remove identification tags.
Psittacines usually nest in hard-to-reach places.
Psittacines will abandon their eggs if approached by researchers.
The number of wild psittacines is very small
3. What point does the professor make about a cattle ranch in Venezuela?
It is home to the largest number of species of psittacines in South America.
The trees that grow there provide a natural breeding ground for parrotlets.
The parrotlets living there have no natural predators.
Its large population of wild parrotlets made it ideally suited for Berg’s study.
4. How were spectrograms useful in Berg’s research?（多选题）
They helped track psittacines as they went in and out of their nests.
They allowed Berg to easily compare a large number of bird calls.
They represented bird calls that were too fast for the human ear to process.
They allowed Berg to conclude that adult bird calls are surprisingly similar.
5. What was one finding of Berg’s study of parrotlets?
After leaving the nest, young parrotlets stop responding to their parents’ calls.
Young parrotlets’ calls resemble their foster parents’ calls more than their biological parents’ calls.
Parrotlets raised in the same nest develop identical contact calls.
Parrotlets use contact calls to attract mates and stake out territory.
6. What point does the professor make about wild psittacines’ need to reproduce their offspring’s contact calls?
It partially accounts for the ability of parrots in captivity to mimic human speech.
It is an instinctual need that is found in many different types of birds.
It cannot be explained solely on the basis of when the offspring leave the nest.
It is not as great as the need of the offspring to learn their parents’ calls.
