I discover 105 active nests, mostly when you’re operating much slower along the surroundings
Throughout the for every reproduction season we wanted nests intensively around the analysis website. I followed new destiny of each and every nest up until the egg hatched and/or colony were not successful. Nests had been decided to go to anywhere between 0900 and you will 1700 era therefore the check outs survived 200 meters from the colony, anywhere between 1000 and 1700 days. Period of this new focal findings ranged out of 31 minute in order to 7 h, together with total lifetime of observance are 31.5 h. Since the the findings ranged long there had been times when you look at the which the male was at the newest colony all day, so you’re able to estimate the fresh new percentage of colony desire i pooled the latest focal observations out-of nests which were at the same stage of incubation.
Because men are more inclined to wasteland new nest when disrupted within an early stage of your nesting stage ( Fernandez and you can Reboreda 2000), we monitored most of the nests (nine of one’s eleven times totaling 34 nest-days) while in the middle- or 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 paras tЕЎekkilГ¤inen treffisivusto 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.
I also mentioned variation during the eggs temperatures inside three experimental nests (nests versus male notice). We utilized nests that had been in past times discontinued while the fresh nests. From inside the for each nest (clutch sizes out of 16, 21, and you can 23 egg) i fixed one-egg having an effective thermistor inside, into the cardio of one’s nest similarly you to we performed to your active nests (discover significantly more than).