May, 1901 
Evolution in the Breeding Habits of the 
Fulvous Tree Duck. 
F or the preparation of this article 
I am indebted to Mr. H. Wan- 
zer, chief engineer for Miller & Lux, 
and C. W. P. Smith, a local collector of 
some note, both of Los Banos, for 1113" in- 
formation on the breeding habits of this 
species from its first appearance in 
Merced county, until last season when I 
spent three months collecting in that lo- 
calit}". 
Mr. Wanzer states that Dettdrocvgna 
fulva was first brought to his notice in 
June 1895, and that they have returned 
each subsequent season, arriving about 
the first of June, and that they did not 
seem to increase until about 1898, but 
since that time have increased with 
such rapidity that the^^ now are com- 
mon summer residents in the irrigated 
districts around Los Banos. 
From time to time since 1895 pot- 
hunters have told wonderful stories of 
finding large numbers of eggs piled up 
on bunches of dead grass and on small 
knolls that rose above the w’ater in the 
swamps. The number of eggs in these 
nests ranged from 30 to 100 or more, ac- 
cording to report, and in not a few 
cases the finder has brought the eggs 
with him in order to prove that what 
he said was true. 
About the 15th of June 1896, Mr. 
Wanzer found a nest, if such it would 
be called, in Camp 13 swamp, contain- 
ing 62 eggs. The eggs were placed on 
a pile of dead grass which had drifted 
together about four inches above the 
water, and looked as if .someone had 
emptied them carefully out of a basket, 
there being no attempt at ne.st-building 
or concealment. Mr. Wanzer took 
tw'elve eggs, three of which are now in 
the collection of W. H. Hayes of Los 
Banos, and the other nine he placed 
under a hen, five of them hatching. 
He states that the young were black 
with a white band around the neck. A 
pen was built for the purpose of watch- 
ing them mature, but they all died 
67 
within a week. I saw quite a number 
of the young last season but failed to 
observe the white band of which Mr. 
Wanzer speaks. The young are very 
diflicult to get as they always make for 
the tall grass at the edge of the water 
at the slightest noise. Those that I 
procured were partly feathered and 
probably" too old to show any indica- 
tion of the white about the neck. 
I found from inquiry among local col- 
lectors and hunters that no one is posi- 
tive of seeing any young of this species 
until the last two or three seasons, and 
I was unable to find anyone who had 
found one of these large clutches la.st 
sea.son. Most of the hunters agree that 
the large clutches are becoming verj^ 
rare, which goes to show that instead 
of colonizing and laying from 30 to 100 
eggs in a set without an 3' attempt at 
nest-building and just out of the water 
on floating vegetation similar to the 
coots, the3^ are becoming civilized and 
are nesting similarly co other species of 
ducks. 
There may be a few Silurians that 
.still per.si.st in colonizing, but if .so, they 
failed to come under my notice last sea- 
son. While I have heard a great deal 
about the eggs being incubated b3^ the 
heat generated from decaying vegeta- 
tion, I have been unable to find an3’one 
who is positive of any of the.se large 
clutches being incubated by this pro- 
cess, .so I think I can safely say that it 
is a mistaken idea with regard to the 
Fulvous Tree Duck, from the fact that 
there is no authentic data of anyone 
seeing 3mv:ng of this species until the 
past few 3’ ears. Also there was no per- 
ceptible increase in numbers until they 
had quit colonizing. 
I collected five sets of eggs of this 
species last sea.son and in ever3^ in- 
stance the nest wms placed on dry 
ground and so well concealed that it 
would be ver3' hard to find without 
flushing the old bird. I found this 
duck not a very close setter, it gener- 
ally flying when I was 20 or 25 feet 
.from the nest. I took 1113- first set on 
THE CONDOR 
