Bat of the Day!

[Uv moth notingha]

Haha ..............just nabbed 2 schwegler 2f boxes , brand new , on ebay for a fiver each ...also the possiblity of getting a 1FQ for £20 .... £120 of bat boxes for £30 , bargin !
Now I will add em to my stockpile until an oppotunity to put a load up comes along over the winter .


UVMOTH

[nightshade]

Google alert turned this one up
BBC News - Bat droppings hit Leicestershire company's expansion plan

[carolinegeorge]

i have just put a bat box on the side of my house but not quite sure if there is anything else i should be doing . doing a blog on urban nature and the trials and tribulations.

[The Woodman]

Three calls involving downed bats on Friday. One of them has come into care, one of last years common pipistrelle youngsters.

A couple of fine days must have roused them from torpor. The little fella is doing well and in a week or so will have put on enough weight to be released if weather conditions are appropriate.

[Dogghound]

I have been carrying out a bit of a experiment this winter to see the difference between two bat detectors/recorders. The Anabat my favorite (the white box on the left) and the SM2BAT which is growing on me (the green box on the right).


As well as testing the two out it also gave me an opportunity to look at two differnt areas within close proximity. Both boxes were placed in the entrances of old buildings to offer the box protection rather than target bats in the building (although this was a bi-product). One building is in the base of a small stream valley and the other 100 metres up a hill on the edge of woodland, in the same field.

I wont bore everyone with my findings, but I did with the exception of a three week period (January) and the odd cold night record common pipistrelle almost all winter, which I attributed to a large pile of cow and horse dung besides the building near the woodland. On a couple of evenings I went to change the batteries (Late November) at around 2-4pm and had a range of common pipistrelles happily feeding over the top of the dung on the woodland edge.

This links to the theory (or reality) that pipistrellus simply cannot hibernate all winter as they are physically unable to put on enough fat reserves to survive. In cold winters like the last one, I personally found that pipistrelles were down, anecdotally, over 100 surveys. I suspect a combination of using fat more rapidly to stay warm and not being able to forage (through low temperature and low prey densities) must have caused this.

I also recorded brown long-eared, soprano pipistrelle and noctule but no Myotis spp. Which given the latter groups hibernation habits I was rather expecting. I have removed the boxes now as spring appears here and I was only really looking at winter habits. Both detectors worked well, but I find that the SM2 seems to pick up animals over a greater range, but this could maybe be due to the settings. I tried them both together in October and found anabat picked things up in the barn but SM2 picked things up outside too.

[The Woodman]

That's very interesting Dan.

I have noted similar observations with the pips, common in particular. They are generally the last to enter hibernation and the first to emerge in the spring. The few hibernating pips I have found have been in relatively exposed positions and subject to diurnal variation which must affect their metabolism. Two hibernation sites I can think of, one found during a survey and discovered inadvertently, found bats in temperatures of near freezing with a high wind chill element.

The incidence, albeit low, of recovering downed bats over the winter period with no external agent as the cause sees almost all as pipistrelles. We have had no other species this winter. This points as to their being active as you've surmised. I've also noted prey species too. This winter has seen only one short period of real cold. This is very hard to quantify but there is a number of insect species active during the winter, gnats and some smaller moths for example.

Are there any times at night that your survey has indicated maximum activity?

I'm not convinced about the selection of species ability to store fat. Consider a 6gm common pip to the similar weight of a soprano or whiskered / Brandt's. How does that stack up?

That's a very interesting post.

[Uv moth notingha]

I am trying to get to grips with bat sounds using the Bat conservation trust bat sound libary , but it is pretty tricky , hopefully I will have enough know how by the time I get my hands on a detector in a few weeks . Interesting ideas about pipestrelles not hibernating for long periods , but I have what I suspect are common 45 pips in good numbers in my area and despite looking out for them in the winter and even in the last few very mild evenings they haven't shown up .

UVMOTH

[Dogghound]

Originally Posted by The Woodman

That's very interesting Dan.

I have noted similar observations with the pips, common in particular. They are generally the last to enter hibernation and the first to emerge in the spring. The few hibernating pips I have found have been in relatively exposed positions and subject to diurnal variation which must affect their metabolism. Two hibernation sites I can think of, one found during a survey and discovered inadvertently, found bats in temperatures of near freezing with a high wind chill element.

The incidence, albeit low, of recovering downed bats over the winter period with no external agent as the cause sees almost all as pipistrelles. We have had no other species this winter. This points as to their being active as you've surmised. I've also noted prey species too. This winter has seen only one short period of real cold. This is very hard to quantify but there is a number of insect species active during the winter, gnats and some smaller moths for example.

Are there any times at night that your survey has indicated maximum activity?

I'm not convinced about the selection of species ability to store fat. Consider a 6gm common pip to the similar weight of a soprano or whiskered / Brandt's. How does that stack up?

That's a very interesting post.

There is a clear peak in activity between 4-8pm presumable when the temperature and insect activity is at its highest. Rather than a prolonged feed through the night, there would appear to be a glut in this population that occurs in this early evening period.

Interesting, I believe the two hibernation strategies of Pipistrellus and Myotis affect the fat storing capacity/metabolism. Myotis in their stable hibernacula (which they enter earlier and leave later) are more suited to prolonged spells in hibernation and are less affected by temperature fluctuation or need to feed. However Pipistrellus I believe is more of a opportunist that sacrifices a stable safe hibernacula for more numerous less stable hibernacula which are possibly closer to foraging areas etc and give more of a selection on where they can forage. This method means they are more able to utilise winter food sources but less able to hold down enough fat due to temperature fluctuations. This would then link to your observations of finding pips in odd winter locations, it would perhaps explain why Pipistrellushibernate where they do and it would explain my findings this winter.

It is also interesting how Pipistrellus is more often found in stable hibernacula in Europe. Is this linked to temperature? foraging habitat? or population size?.

I have always associated them with buildings in the winter but is this due to warmer temperatures for hibernating or is it because of the associated farm yard, sub-urban invertebrate food sources?

If they were not intending on being active all winter then perhaps the Myotis strategy would make more sense, although this does not correlate with species like brown long eared which are quite active during the winter but prefer stable temperatures?

And does it actually make ecological sense to risk temperature change just to feed, when you could find a really stable area and just hide away all winter? perhaps another reason is involved?

Im not sure if this hypothesis is onto something or not? As always Woodman I appreciate your input, it just feels good to be having a discussion about bats again. I dont think any other group of animals leaves me with so many questions and theories.

[Dogghound]

Originally Posted by Uv moth notingha

I am trying to get to grips with bat sounds using the Bat conservation trust bat sound libary , but it is pretty tricky , hopefully I will have enough know how by the time I get my hands on a detector in a few weeks . Interesting ideas about pipestrelles not hibernating for long periods , but I have what I suspect are common 45 pips in good numbers in my area and despite looking out for them in the winter and even in the last few very mild evenings they haven't shown up .

You will soon pick it up, for now I would try to learn the common species and become familiar with them. In time learning the others will become easier as you will know the familiar calls, others will stand out. It is daunting at first but just enjoy it and dont get too bogged down learning them all. It is also worth learning as much about bat species biology as you can as this can aid ID enormously. Even getting a general idea of how different bats fly and look can help. The dark belly of the pipistrelle can be distinctive in the field as can a large noctule circling above a tree line.

Where have you been looking for pips, what kinds of habitats? If you can get to a sheltered pond, dung pile or livestock shed (with livestock in it) these are good areas to look in winter. Anywhere with nutrient rich water, sheltered animals, dung or decaying vegetation really. Any activity at this time of year is going to be quite localised around high food aggregations. However bats do hibernate and despite my posts activity is generally very low in winter,but it is so mild at the moment its well worth looking.

[Uv moth notingha]

hi again . I dont paticulary want to waste your time on the retorical bat detector questions , but I have seen a Batbox III (the old version , without a lcd display ) on ebay which it looks like I could get for under £50 , which seems like a good price for a quality detector . I was going to save up a bit more and go for a magenta bat5 , which would clearly be brand new , with a digital display , and look nicer , but cost around £100 .
Any advice would be appriciated , as lots of talk about detectors and recording devices (anabat etc ) seems to go on this thread .

Thanks
UVMOTH