While doing so, into the eleven most other nests we registered eggs heat playing with a small temperature logger (Tinytalk-temp, Orion Parts, Sussex, United kingdom)

We receive 105 effective nests, primarily while you are driving slower along side surroundings

Throughout the for every reproduction 12 months we wanted nests intensively around the analysis website. I used the new destiny of every colony until the eggs hatched or the colony were not successful. Nests was basically visited anywhere between 0900 and you will 1700 times in addition to check outs lasted 200 meters away from the colony, ranging from 1000 and you may 1700 days. Length of the brand new focal observations varied out of 30 min so you’re able to eight h, while the full duration of observation try 30.5 h. Because the our findings ranged in length so there had been times inside that male is at the brand new colony for hours on end, so you can guess the latest part of colony interest we pooled the fresh focal observations away from nests that were in one phase out-of incubation.

Since men are more likely to desert the fresh nest whenever disrupted within an initial phase of your own nesting period ( Fernandez and you may Reboreda 2000), i monitored a lot of nests (9 of one’s 11 cases totaling 34 nest-days) through 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 Trykk pГҐ denne lenken. 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.

I in addition to mentioned type into the egg temperature when you look at the around three fresh nests (nests in place of male attract). We utilized nests that had been in past times deserted as the fresh nests. Inside the for every nest (clutch products away from sixteen, 21, and 23 eggs) we repaired one egg which have an excellent thermistor inside, to the cardiovascular system of one’s nest similarly one we did on the active nests (come across a lot more than).