Nico's type A
Nico's type B
Enrico's type D
Enrico's type E
Luciana's type I
Albert's type K
Cooper's type N
Cooper's type O
Harry's type V
Harry's type W
call type AE
call type K
call type GG
A)
B)
C)
Dimension 1
Dimension 2
Dimension 2
Dimension 1
-1
0
1
-1
0
1
1
0
-1
1
0
-1
Nico
Enrico
Luciano
Cooper
Harry
Albert
GROUP 1
GROUP 2
100 ms
5
3
1
5
3
1
5
3
1
Type AE
Type AE
Type AE
Type K
Type K
Type K
Type GG
Type GG
Frequency (kHz)
Frequency (kHz)
Figure 4.5. Contact calls from two social groups of male budgerigar. (A) Multidimensional scaling of five renditions of each bird’s dominant contact call before
contact and (B) after 8 weeks of social interaction. (C) Sonograms of dominant
contact calls for each male after 8 weeks of contact have similar structure and thus
show convergence within each group. (From Farabaugh et al. 1994. Copyright
© 1994 by the American Psychological Association. Reprinted with permission.)
172