We did some interesting modifications on the equipment. The Ibutton temperature loggers we use to investigate incubation patterns and a possible isolating effect of dung are tiny (about the size of a penny or a 5-cent-piece, 16 mm) and very light. No chance that we would find them again in the steppe if the bird decided to remove it, and why wouldn't they. The larks for sure are capable to remove it, as carrying pieces of horse dung is not a problem for them! Digging into the literature we found some clever ideas to overcome this problem. What we now did (at least for one temperature logger for the moment) is to attach Velcro to the top of the button and to the top of a 16 cm long nail. We will push the nail into the soil beneath the nest, so that only the button sticks out. For sure the larks will not remove it now, at least that's what we hope. By using Velcro we can easily detach the buttons to be able to read them more easy.
|Ibutton temperature logger with velcro|
|They fit snugly to this nail!|
We were wondering if the metal of the nail had an influence on temperature measurements, so we tested temperature logging with loggers mounted on nails versus loggers put on the soil. There seems to be a small temperature buffer effect of the velcro/nail combination when compared to loose Ibuttons, i.e. temperatures were approximately 0.5 degrees higher when using our construction. So we decided to mount all Ibuttons on nails, also those that are used outside nests. In this way the buffering applies to all Ibuttons and won't cause any problems in comparative analyses.
|The papier-mache eggs before...|
|...and after a herd of students passed trough!|
|Using small wooden sticks to pin the "eggs" into the soil so they are not blown away.|