We discovered 105 productive nests, mostly while operating slower along side land
Throughout the for each breeding year we wanted nests intensively everywhere the research webpages. We followed the brand new destiny each and every nest till the eggs hatched or perhaps the nest were unsuccessful. Nests was went to ranging from 0900 and 1700 instances together with check outs live 200 meters from the nest, ranging from 1000 and you will 1700 period. Amount of new focal observations ranged of 31 minute to help you seven h, while the full duration of observance are 31.5 h. While the our very own observations varied long and there were times into the that male is at brand new nest right through the day, so you can guess brand new portion of colony interest we pooled this new focal observations from nests which were in one stage away from incubation.
As men are more inclined to wilderness the latest colony whenever disrupted on an initial phase of your own nesting duration ( Fernandez and you will Reboreda 2000), we tracked almost all of the nests (nine of 11 cases totaling 34 colony-days) through the mid- otherwise later incubation
The thermistor of the temperature logger was introduced in a fresh natural orphan egg (unattended eggs laid far from active nests; Navarro et al. 1998) through a small hole in the equatorial plane and fixed to the eggshell with epoxy adhesive. The egg was attached to the center of the nest and the data logger was hidden under the nest. The data logger automatically recorded the temperature at 3.8 or 6 min intervals during four or six days, respectively. We monitored egg temperatures in those 11 nests totaling 40 nest-days. In the other two cases we started the monitoring of the nest three and five days after the laying of the first egg. None of the nests used for monitoring male activity was deserted. We used the decrease in egg temperature to determine when the male left the nest ( Hainsworth et al. 1998, Flint and Grand 1999). We previously estimated egg cooling-rate of Greater Rhea eggs by heating six fresh eggs up to 33°C and then placing them in an environment at a temperature of 25°C, similar to temperatures registered in our study area between 1100 and 1300 hours (the warmest time of the day). We estimated egg cooling-rate by dividing the initial difference in temperature between eggs and the environment by the time elapsed until eggs reached a thermal equilibrium with the environment. The estimated egg cooling-rate for a temperature gradient of 8°C was 0.063 ± 0.01°C min ?1 . We assumed that the male left the nest when the difference in egg temperature was |T(t) ? T(t?1)| > 1°C, where T(t) and T(t?1) are egg temperatures at a time interval of 15 min when data loggers were set at 3.8 min intervals or 18 min when they were set at 6 min intervals. We considered that the male was outside the nest since the time at which the difference between T(t) and T(t?1) was negative until the time it was positive (i.e. the male resumed incubation). Although the sun can heat eggs when the male is absent (particularly at midday), unattended eggs never reached temperatures >30°C (see below). Therefore, it was possible for us to discriminate between an increase in temperature produced by the Sun and one produced by males when they resume incubation.
We along with counted version into the eggs temperatures during the about three experimental nests (nests Ukrainsk chatterom instead male interest). I made use of nests that were in past times deserted because the experimental nests. In for every single colony (clutch products out-of 16, 21, and you may 23 egg) i fixed one egg that have a great thermistor into the, with the cardio of your colony similarly that i performed for the productive nests (get a hold of over).