Chick timers are a “smart” kiwi radio transmitter developed by a couple of clever engineers in Hawkes Bay. They were sick of doing heaps of night field work on their local kiwi recovery project checking kiwi nests to see if chicks had hatched.
These guys (John and Al of Wildtech) have taken a standard kiwi chick tx (“tx” is short hand for transmitter) with a mercury switch inside it and added some software.
The mercury switch detects movement and the software basically counts how often the kiwi moves his leg. High counts mean lots of movement. The software then interprets the trends in movement and sends out a coded signal in a data stream that we can monitor with our standard kiwi radio monitoring gear as series of beeps. We put these tx’s on the males because it is the dads that incubate the eggs after mum has made a huge effort to lay them.
Illustration from Heather Hunt’s Kiwi: The Real Story
When the dads are nesting their activity is usually around the 3 to 4 hour mark. This is the time it takes the dad to sneak off the nest for a quick feed each night. He usually nests for 80 days – the longest of any bird species.
This is a photo of Dallas’s data stream written in Todd’s notebook on the 9th January 2015
Todd has interpreted Dallas’s data from his note book. The table below explains what Dallas’s data stream is telling us about Dallas and his chick.
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48 |
This is the background ‘pulse’ of 48 beeps per minute, which tells us Dallas is nesting (a pulse of 30 is non nesting ) |
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10.10 |
This shows he’s been on the nest for 88 day ‘Days on nest ‘ (you subtract 2 from each number of beeps so 10.10 becomes 88) |
|
2.4 |
Shows he hatched a chick 2 days ago (2.4 subtracting 2 from each number becomes 2) |
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2.2 |
This indicates the days since a nest is finished in this case 0 days (2.2 — subtract 2 from each number is 0). This will get triggered when Dallas stops nesting |
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3.4 |
Shows 12 hours since Dallas got up last night i.e. he got up at 2.30am last night for a quick feed |
|
3.2 |
Shows battery life, there are 10 weeks left |
|
3.9 |
Shows his activity last night in 10 minute bursts i.e. 17 ten minute bursts is 170 minutes which is about 3 hours activity . Time for Dallas to have a quick feed and get back to the nest before the 2nd egg gets cold |
|
2.11 |
Shows his activity the night before last, it was only 90 minutes. He was with a newly hatched chick Dallas stayed on the nest almost all night |
|
3.4 |
Shows his average nightly activity for the past 4 nights was 120 minutes . |
These chick timers have been great for monitoring our kiwi. We use them on the dads in Purua that are part of ONE programme to tell us when a chick has hatched and is ready to be moved to the Limestone Island kiwi crèche. They save heaps of field work time that was previously needed to visually check kiwi to see if they were nesting. These transmitters also mean the kiwi are far less likely to be disturbed by whoever is monitoring them because they can do it from a distance.
