Bat box check at the Organ Pipes, 19 April 2015

Written by – Robert Bender
New Picture (2)
New Picture (3) New Picture (4) New Picture (5) New Picture (6) New Picture (7) New Picture (8) New Picture (9) New Picture (10) New Picture (11)We had a drizzly day, with occasional showers. Connor decided to try the harness and did much of the ladder climbing with my group, while Steve did the other end of the valley.

We had a visitor from Canberra, David Andrew, of the federal Environment Dept, on a quick visit to Melbourne.

Freetails were in 5 boxes, the biggest group in C42.

David’s umbrella came in handy during showers to keep bats dry. One Freetail escaped and was chased by a peregrine falcon.

There were Gould’s in 16 boxes, including 10 quite large groups.

I’d forgotten the Visitor Centre key, so Robert Irvine let us into the Friends’ shed (Jack Lyale’s old office from 1973). Crowded but workable. Lights set up, equipment laid out and the team went to work.

There were four tables for processing. Steve chipped 13 new Freetails so we now have a total of 72.

Pia had sister Lulu to scribe for her. 82 new bats were banded. Casey was there with his parents, visiting from San Francisco.

Lindy was helped by Pia’s mother, Mary Long

Of the 257 bats processed over the evening, only one had an injury, judged to be a 3, with a band embedded in the forearm. Lindy managed to prise it off, medicate the wounded arm and put another on the other forearm.

Lindy suggested I take a group down to start releasing while the rain held off. So a line-up of eager bat releasers opened bags, to find as usual that Freetails take their time to consider the situation.

There were 19 Large Forest bats in one box, which all flew off quickly.

By the time we had released the first bunch, the last bats had been processed, so we went down again and released them, and were all done by 9:30. That was a great improvement on the good old days when we’d sometimes finish up at 2 a.m. Having a big team of bat handlers and scribes makes a difference.

Looking at the number of months since a bat was banded shows they are a mix of ages, some clearly young of this breeding season which may have involved two successive litters by some Gould’s, some are between 1 and 2 years old, and one is over a decade old. Nearly all the old ones are females.

Summarising that into age in years, there were 114 young bats, newly arrived at adulthood from birth last spring, 26 over one year old, including probably some immigrants that dispersed from other birth colonies, another 20 between 2 and 3 years, and 42 at least 3 years old. Again, as we only started banding in Dec 2012, we don’t know how to divide them into bats aged 3, 4, 5 or more years old. The only securely dated one is 88866 who is over 10 years. So there may be some 9, 8, 7 etc. years old in the 42 older bats. We’ll have a clearer idea of the age structure of the colony in another 5 years or so when we have a longer history of banding.

17 of the 23 freetails were assessed as post-lactating females with only 2 preparous, so our boxes seem to be a post-breeding holiday camp for mothers needing a recuperation time after an intensive childcare period. One female, chipped in Apr ’13, has now been captured 5 times, so is a regular user of our boxes, always appearing April to August, never during the breeding season. Another female, now captured 4 times (not this month) has been in a box twice in April, twice in December, so has different habits.

Simone set up a beautiful set of photos on his website as a wonderful record of our day: https://www.flickr.com/photos/124310560@N08/sets/72157651610834947/

Tally for the Organ Pipes

Box Bat Species M      F
C44 32 Gould’s 9 23
C24 27 Gould’s 9 18
C30 23 Gould’s 5 18
C29 21 Gould’s 1 20
C19 19 Lge Forest 1 18
C36 19 Gould’s 10 9
C23 17 Gould’s 7 10
C32 16 Gould’s 5 11
C28 14 Gould’s 14
C13 10

1

Gould’s

Freetail

1 9

1

C40 10 Gould’s 1 9
C42 9 Freetail 2 7
C15 8 Freetail 2 6
C35 8 Gould’s 5 3
C05 5 Gould’s 5
C20 5 Gould’s 1 4
C17 4

2

Gould’s

Freetail

3 1

2

C41 3

1

Freetail

Gould’s

 

1

3
C25 2 Gould’s 1 1
C01 1 Chocolate 1
  257 Totals 70 187
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About Pia Lentini

Pia Lentini is a Postdoctoral Research Fellow with the University of Melbourne's Quantitative and Applied Ecology group.
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