Ornithology, Evolution, and Philosophy 123

University Student in Greifswald and Berlin 25
(12) Test by aviculture whether the two species of treecreepers, the willow tit and
the marsh tit, the sprosser and nightingale, etc., can be crossed in captivity
(like the horse and donkey).
(13) Investigate the degrees of relationship among species of a single genus, for
instance Charadrius dubius and hiaticula.
(14a) Do only such species hybridize in which the female alone raises the young
(Capercaillie, etc.)? Or also such others that are very similar in their whole
reproductive biology?
(14b) How helpful is microscopic analysis of feathers in order to distinguish between
juvenile, female, and male plumage?
(15) Investigate the distribution of Muscicapa hypoleuca, semitorquata, albicollis.
(16) How far north does the osprey range? Migrant ducks from further north or
east passing through Moritzburg, were afraid of it on 12 September 1923.
(17) Is it legitimate to make anthropomorphic descriptions of birds, as done by
B. Hoffmann?
(18) How independently has the beauty (a relative term!) of bird songs evolved?
(19) Closely related species of birds often differ strikingly in the length, structure,
and elaboration of their songs (B. Hoffmann).
(20) Different species of birds differ strikingly in the tonal quality of their songs.
(21) What is the psychological significance of the various call notes of a species
(fear, pleasure, etc.)?
(22) [A repeat of question 5] B. Hoffmann, p. 21
(23) How differently do different nations represent the vocalizations of the same
species of birds?
(24) To what extent do females sing? (Hantzsch) Which calls are shared by male
and female?
(25) If the song of the male serves to attract females (Hoffmann, p. 93), why do
birds sing also long after the period of pairing and frequently even in the
autumn? (J. Ornithol. 1917, II, F. Braun)
(26) Can birds really count up to three? (B. Hoffmann, p. 120).
(27) When searching for bird nests, always record how far away from the nest
the male was singing.
(28) Find out how many clutches per season the willow tit raises, and search for
their nest. Willow tits tend to spend the night in their nest cavity.
Despite the birds, Mayr attended all his medical courses very conscientiously
exceptforhisstayatafarmforacoupleofweeksduringthefirstsemestertohelp
with haying in order to get something to eat (in 1923 the inflation in Germany
was rampant and food scarce in the cities). After some difficulties he had found
a furnished room in Burgstrasse 17. He had to go down a staircase and cross a yard
to get to a toilet. There was, of course, no heat, no warm or running water, only
a wash basin (where the water sometimes froze in the winter) and a pitcher with
water to fetch somewhere from a faucet. His lunch in the mensa, the student dining
hall, consisted mostly of a rather thin soup.
Mayr disliked the student fraternities and their activities like dueling and drinking
and turned down their attempts to enroll him. Eventually he joined the Deutsche