We found 105 active nests, generally while driving slower along side landscaping
During the for each and every breeding 12 months i sought after nests intensively all-over the analysis webpages. I then followed the new destiny of each and every colony up until the egg hatched or perhaps the nest unsuccessful. Nests was in fact visited anywhere between 0900 and you will 1700 period together with visits survived two hundred yards out of the nest, between 1000 and you will 1700 circumstances. Period of new focal findings ranged out of 29 minute so you can 7 h, in addition to complete duration of observance is 30.5 h. Just like the the observations varied in total so there had been cases for the that the male is at this new colony right through the day, to estimate new percentage of nest attention i pooled this new focal findings regarding nests that have been at the same stage off incubation.
Once the males may desert the newest nest when disrupted within an initial phase of nesting duration ( Fernandez and you can Reboreda 2000), i tracked a good many nests (nine of one’s 11 circumstances totaling 34 nest-days) throughout the middle- otherwise late 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 and additionally mentioned variation when you look at the egg temperature inside the three fresh nests (nests rather than male attract). I utilized nests that had been Ha et glimt pГҐ nettstedet prior to now left behind as the fresh nests. Within the for every colony (clutch designs out of 16, 21, and you may 23 egg) we repaired one-egg which have a thermistor in to the, towards cardio of the nest in a similar way that we did to the energetic nests (select above).