these fibres as they dry out. They form the covering of the bulb. Examination of the old nest revealed almost no twigs at all. That is there was substantially none of the first class of material. The nest began with the second class, which in this case, consisted of narrow ribbons of the deciduous bark of the honeysuckle--very handy for Neo as he did not have to go far for material. And this explains why he was not conspicuously in evidence during construction. The lining was perhaps more than 99% soap-root fibre: the remainder being a few manila rope threads. The interstices of the lining were almost completely filled with sheaths of the chicks' pin feathers. It had not been fouled in the slightest and there were no ants in it. These two nests of Neo's (and the two classes of nests in general) clearly illustrate the capacity of the thrasher to adapt his structure to the type of support available--immediately--without trial and error. (10:35 P.M. Horned owls hooting outside. Not so good!). The thrasher, therefore, has someplace in his makeup, either through inheritance or individual mentality, some attribute that en- ables him to predetermine the type of structure suitable to two dif- ferent kinds of locations. Except during the early part of the forenoon and at night, Rhody occupied his nest 1-38 little of the time. He gave the im- pression of searching for a location for a new nest. He does not ap- pear to have done any more work on 2-38. He refused to take either of the two mice that he killed and abandoned yesterday, waiting patiently until a live one was produced. This was received full ritual, presentation at the magpie cage and the mirror and was finally eaten in nest 1-38. April 25th. Neo was working on his new nest at 7 A.M. and by 8 o'clock had done a surprising amount of construction. As thought yesterday, the rough work had been done --apparently all in one day--and he was using finer material exclusively. After 8 A.M. he fed the young birds faithfully with worms furnished by me and, as late as 10 A.M., was not seen to work again. Rhody was in his nest at 7 A.M., but at 8 A.M. and up to 10, could not be located. The swelling at the break in the lower mandible of the crip- pled thrasher has increased, resulting in forcing the tips farther apart. Otherwise he appears to be doing well--is bright and inter- ested. Rhody found me at 12 M. and had a mouse. He spent the rest of the day at home loafing. At 5:45 he was stowed away in his house in the peppermint gum. Neo was not seen to work after 10 A.M., but sat in his nest occasionally. The crippled thrasher again, about sunset, became restless and tried to find a higher place within his cage to roost for the night, calling. He subsided more quickly this time when covered. April 26th. Rhody was not in his nest at 7:20 A.M. and was found sitting on the bank of the Nichols' garden, looking off to the west. He cried on seeing me and responded to my invitation to come home and