Concurrently, inside the eleven almost every other nests we entered egg temperature having fun with a mini heat logger (Tinytalk-temp, Orion Elements, Sussex, United kingdom)

We receive 105 energetic nests, generally if you find yourself driving much slower over the landscaping

Throughout for every single breeding year i searched for nests intensively all over the study web site. I implemented the newest fate of every colony until the egg hatched or even the nest failed. Nests was indeed went to ranging from 0900 and you can 1700 occasions plus the check outs survived 2 hundred m out of the colony, between 1000 and you may 1700 circumstances. Period of the fresh focal findings varied of 30 min to 7 h, and overall duration of observation is actually 31.5 h. While the our findings ranged long there was indeed instances when you look at the that male was at the fresh nest for hours, so you can imagine the part of nest appeal we pooled this new focal observations regarding nests which were in one phase regarding incubation.

Just like the males will wilderness the new colony when interrupted on an early stage of your nesting duration ( Fernandez and you can Reboreda 2000), we monitored a lot of the nests (9 of your eleven circumstances totaling 34 colony-days) while in the middle- 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.

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I in addition to measured variation in egg temperatures for the around three experimental nests (nests in the place of men desire). I utilized nests that had been in earlier times discontinued due to the fact experimental nests. Inside the for each and every colony (clutch systems away from sixteen, 21, and you may 23 egg) i repaired one egg which have a beneficial thermistor into the, toward cardio of your nest similarly you to definitely i performed toward productive nests (look for over).