DBQ p. 328- Birdsong- Innate or Learned?
1. Both sonograms I and II display Z. leucophyrys songs of similar durations and frequency ranges. Hweover, the patters of I and II are slgihtly different: while I ends in a pattern of short wavelength sounds, II ends in a decreaseing frequencey patternw with detached sounds.
2. (a) Sonogram III shows a similar duration as with sonograms I and II. Sonogram III ends with a sequence of decreasing frequency notes like in Sonogram II, while sonogram I displays a pattern at the end with short wavelength sounds generally constant in pitch. Furthermore, while sonograms I and II have finer, short wavelength patterns in the second parts of the songs, III shows a less distinct, less fine patter at this part of the song.
(b) The song of white-crowned sparrows is both innate and learned. If the third sonogram is the rudimentary template subsoung, it means that the initial song they know is a result of genes- innate behavior. When seeing sonogram I, this RTS is modified, most likely due to hearing other males’ songs during the critical period of imprinting- learned behavior. Hence, it can be concluded that the song of this bird is a result of both types of behavior. On the other hand, one might say that other males’ songs have no influence and so the variations in I, II, and III are purely innate.
3 (a) Both sonograms V and IV are similar in duration and the general frequency range. However, while V begins with a sustained note of one frequency, IV begins with a series of notes of differing frequencies.
(b) Both sonograms V and I and II are similar in duration and show similar patterns. However, sme patterns are different between V and I and II: while the second part of the song with high-wavelength sounds are shorter in V, they are longer in I and II and the middle part of the song does not follow a distinct pattern in V, whereas in I and II, there are.
(c) One reason why birds rarely imitate other species is that they do not recognize other species’ songs because they are too different from their rudimentary template subsongs. Another reason is, it would be a disadvantage for a bird to learn a different bird’s song because they would end up attracting the females of the other species.
(d) This observation is evidence for learned behavior because the hand-reared birds of V sing a similar song with a different species (strawberry finch- the general frequency, range, parts of the pattern between V and III were similar). However one can refute this argument by saying that these similar parts between V and IV are not a result of imitating the strawberry finch’s song but is a result of imitating a white-crowned sparrow’s song with a similar pattern.