Nest Sensor Setup (part 2)

I finally got out in the garden again to day to complete part 2 of my bumblebee sensor project.

The system has been up and running for a week, measuring temperature and light levels, but I needed to tackle two things:


  1. The outdoor temperature sensor was too exposed and over-reading in direct sunlight; and was too close to the garage wall, so also picking up heat from the wall
  2. I still had to finish constructing and fit a flap sensor to monitor activity in and out of the nest


For the thermometer, I hacked a small bottle apart and fixed it up with my new favourite "stuff for making things with": Sugru. Here is is below with the iobridge board in the background. 


a bottle to hold the outdoor thermometerNext I just spray painted it with some plastic paint - so it would blend in a bit and be protected from sunlight. Only a rough job - good enough!

bottle spray painted & fixed together with SugruThe thermometer (white wire) runs up a small tube in the neck of the bottle where it is shieled from the elements. Then it is simply mounted on a cane round about nest height, and away from the garage wall.  

thermometer on a stick!In comparison with our wireless weather system, my DIY thermometer was only reading 0.2C difference, which I am very happy with. 

Flap Counter

Next up was the flap sensor. Getting a good flap sensor running has been critical for me this year, because I want to use it to closely correlate activity data with enivronment data. I was only able to do this last year in a minimal way because it's so labour intensive (to do from CCTV).

While this initial system will not give me the reliability required to accurately count bees in and out (it's not directional anyway) what it should do is give me activity levels throughout the day (e.g. first, last, flights during bad weather etc.) which will definitely be a step forward. 

The system is comprised, essentially, of an alumiumium foil strip attached to the side of the flap that acts as a make/break switch on the ioBridge digital input. When the flap is closed, the circuit is made, and the digital input is held low. Once a bee pushes through the flap, the circuit is broken, which generates a digital pulse that the ioBridge board can count. 

flap sensorIt's taken quite a bit of experimenation to get the inputs working in a way that is meaningful. Opening and closing the flap doesn't just generate a single pulse but can generate many (the bumblebees themselves very rarely just open it cleanly - but push against, causing it to open and close); so I can't rely on this basic circuit to count single open/close of the flap. 

But it doesn't really matter as the system will count the total number of activations and report this every 10 minutes. These 10 minutes slices will give an indication of the overall activity level, and in particular detect things like 1st & last exits, which I'm particularly interested in. 

This is only a phase 1 system - to get me started and get some data collected; I have ideas/plans for two further developments of this system - one using a light beam sensor (this would solve the problem of the flap being so busy that it actually gets held open and only counts a single pulse for many bees) and also a non-contact displacement sensor which will measure the exact angle of opening. Ideally a combination of these two would be good - but I don't have enough inputs at the moment. 

So, I have to wait for a few days now to collect some data and see how the system performs. 


Bumble infrastructure & Beepol modifications

A busy day today. Busier than the bees, as it was cool and windy, so I only saw one Bufftailed queen foraging on our heather. Meanwhile I was completing off all our "infrastructure" preparations - namely the nestboxes and CCTV. 

I've created a "photo diary" of what I did, which included some desired modifications to our beepol lodge - I hope fellow bumblers will find them useful. 

beepol lodgeAbove is the beepol lodge with last year's modifications - namely the extension to hold the external entrance camera. You can also see the new wax-moth entrance flap, which screws on as an attachment. This is new for the 2012 season. Everything else about the lodge is standard. 

bumblebee nest boxesAbove our our other two nestboxes. These have had various modifications from 2011 and one of them we can now add sugar/honey-water to from outside. I prepped them internally last week, but needed to check/reset the cameras and install thermometers. 

On the right is my fake "hill" - it covers the next box and can be placed up against a wall to disguise it. The idea is to make the bumblebees think the box is underground. We put lots of plants and grasses round it to add to the effect. 

fitting & testing the internal entrance cameraThis year we are putting two cameras in the lodge rather than one and thus placing them slightly differentlt. This camera above is trained directly at the entrance hole, and indeed can see right out through it - so I think we'll get some cool shots as bees come into land and come through the entrance. But also, the other reason for placing it this way is so that we can use the movement detection on the DVR to more reliably count bumbles in and out of the nest. 

2 cameras installedAbove 2 cameras are now installed - one will point down more into the nest so we can see activity below. They are quite fiddly to place and also to decide the best view when there is no nest in the box - but I have to assume that two cameras will be better than one! The other wire dangling down is the thermometer: more on that later. 

embedded thermometer on bumblebee lodgeThe next job I undertook was to embed a thermometer in the extended entrance porch. This was no easy job - it took the best part of 90 minutes to disassemble and drill/file out a hole and get it all back together again without breaking it - it's quite soft wood. But I'm really pleased with the result. The thermometer wire runs through a hole in the back and into the second lodge entrance which would otherwise be blocked, and is attached inside to measure the ambient temperature inside the nest. It's going to be a pain if the thermometer dies or needs its batteries changing, but so be it! I tried many variations of attaching the thermometer to the inside and outside of the lodge, but this is the neatest and also the thermo is visible to the external camera, which is a big help when reviewing footage. [That's a top tip from last year: it's very useful to have the temperature visible on camera].

view from external entrance cameracable tidy at rear of lodge

The next job (above) was to start tidying up the cabling at the back of the lodge from all the cameras. Some tacked-in cable clips do the job and makes the whole process of moving the lodge a bit easier and safer. 

sealing the edges against wax moth Next I attached some velcro along the edges of the box base. This is only the "loops" part (softer) and not the "hooks" part: we don't want the box to stick together, we just want all the imperfections and very slight gaps in the wood sealed over - the sticky-backed fabric is perfect for this. 

creating a bumblebee sizing chartAnother feature we wanted to add after last year's experiences was some kind of "sizing" chart inside the box, so that when bees move across the field of view we can get some indication of their size. This is useful for understanding whether they are queen, boy or girl, or under-formed etc. And also for indentifying the bee when there are only a few in the box. I discovered the graph paper didn't show up well on the camera, so i first marked all the corners in black pen. But that didn't show up on the infrared, so I had the brainwave of poking a hole at each corner and mounting the graph paper on some diamond grade high-visibility - the result is excellent under infra-red. 

view of size guide in daylightglowing "dots" on the size chart under infraredHowveer, when the lodge is closed and the camera switches to infra-red, the high visibility backing creates a series of glowing "dots" at 1cm spacing. This will be perfect for assessing the bee sizes as they enter and leave. 

base for the beepol lodge and shelterFor the base of the lodge this year we are using an old plastic board, with some extra high vis tape for grip. Also, the bees will be able to use this bright colour to memorise the nest location very easily, so if we needed to move it around the garden a bit, they should find their way back in ok! We are using this base instead of putting the lodge directly on the stones, just to help a bit in situations where bumbles fall from the nest, so that they don't get lost or buried in the stones directly underneath.

a nestbox in situ - with its "disguise"Above is one of the completed nest boxes on its site. It is partially buried and disguised by the expanding foam shelter. More grasses and heathers to come. We wil not interfere with this box and just hope that some nest searching queens explore it and choose to use it. You can see it also has an embedded temperature guage. 

The beepol lodge in situ, showing thermometer workingAbove is the beepol lodge in its intended location. The thermometer is working a treat! The shelter is not strictly necessary but we are just shading the box a little and also protecting it from rain. The bricks are greased round the side and help to keep ants from getting into the nest. 

both east-facing nest sites: beepol lodge and disguised nest box

internal layout of 2nd nest boxAbove is the internal layout of the 2nd nest box. This box has two cameras for greater coverage and i've created a tube at the back to supply food. This could allow us to keep a queen captive if we wish to try and oblige her to brood. The food would go down the tube into the pen lid attached to the side of the box. This box will be sited south facing at the rear of the garden and will be less disguised. This is the one we'll use to try and brood any queens we capture that are nest searching.

I still have to repatch all the video on the DVR in my studio to get all the right cameras coming up on the right channels with the right names, but apart from that we now just need to wait for the queens to start nest searching in earnest! 









Hibernation Station

Today's plan was to create some hibernation habitat for ours (or indeed) any other bumble queens. I certainly succeeded but before I go on to explain what i did, a few words about Bumble bee hiberation are in order. 

About Bumblebee Hibernation

The survival of bumblebees depends on hibernation. A bold claim, perhaps, but since colonies are annual and do not survive from year to year, the future "survival" (i.e. development) of a new colony is solely in the hands of the new-born queen and her ability to find a good place to hiberate and survive the winter. The future existence of several hundred bumblebees depends on her success. 

I've found very few scientific papers on Bumblebee hibernation (see Bumblebee Links) - one of the foremost appears to be from 1969 with a more recent study analysing that paper and some its weaknesses as well as providing some new data. 

Of course, this stands to reason: it is difficult to track bumblebees in the wild and given that both the process of entering a hibernation spot and emerging from it in the Spring are but momentary occasions, it's more or less down to chance to be in the right place at the right time to observe it. Of course, knowing a little about preferences and habitat could lead one to have a better clue of where to look and perhaps to be able to find bees during hiberation, but such a practice is not desirable. 

Therefore, we have gleaned what we can to come up with a strategy for possible hibernation in our garden. 

What we've learnt so far is that Bumbles prefer a north-facing location (which helps keep the nest coolness required to prevent them emerging too early in spring) and often hibernate in embankments, under tree stumps or roots and sometimes in/under walls. I've not seen an in-depth analysis of the preferences of each species, this may well be an unresearched area. What we do know is that the Queens will tend to burrow down in loose substrate in order to get deep enough not to get frozen during the winter. This is typically 6 - 8 inches, at least for a usual winter.

At first when I discovered this I nearly abandoned my plan altogether - it seemed to me, without getting the bees well underground, I couldn't guarantee their safety in an above-ground nest box, no matter how well insulated. It looked like I could be tricking them into an environment that would prove to be unsuitable for them.

Then, of course, I had my epiphany. Our boxes are equipped with infra-red cameras; basically very small heaters (as we know from how our "indoor" bumbles loved to gather under them) - so we can actually keep the boxes warm. By controlling the on/off times of the cameras we would in fact be able to keep the boxes at pretty much any temperature that is appropriate. I might even be able to automate the process. So, providing I avoid the risk of making Spring seem to come too early, we should be able to keep the bees very safe from a harsh winter - perhaps more so than out in the "wild".

I fully recognise that the chances of getting a queen to choose one of our artifical locations for hibernation is extremely slim, but we have the nestboxes, so there is no harm in trying to put them to good use.  

Box 1

We had two nestboxes to equip for hibernation so I thought I would try two different designs - each may encourage different types of bees or one may provide a better habitat than the other; either way, we will probably learn more by trying two designs rather than one. 

For the first box I placed a layer of very small decorative stones about 2 inches thick at one end of the box. Although the bees are reported to burrow 6 to 8 inches down, obviously this design is not going to allow them to do that. However, I thought it was sensible to give them the potential to burrow at least some distance, especially as the route down into the box is a good 8 inches in its own right. I filled with extra moss then used all of the "nesting material" that the boxes were actually supplied with. This is to fill the available space and provide insulation, bearing in mind that the bees usually burrow down below the surface of the ground so would not expect a "big" open space (unlike the spaces they would choose for a nest). 


There is tubing to take the bee into the depth of the box and, although not visible in the above picture, it is also equipped with an infra-red camera and a temperature sensor. 

I also thought it made sense to try and re-use the "hummock" I had made in Spring as a disguise for the nest box when queens were nest-searching. Not only would this provide extra insulation but would also help with the subterfuge in trying to create a north-facing "embankment". I had the brainwave to actually turn the shelter round so that it was open at the back and could go flush against the wall. I'm not quite sure why I didn't use it like this in the spring; it seems a far more obvious way to improve the disguise of the box. 

All that was required was to drill a hole to take the tube to the nestbox entrance and I decided to embed the thermometer neatly in the surface; here's the finished article. 

Box 1 under its shelter

I'm actually rather pleased with it!

Box 2 

Box 2 is our original "master" nestbox, which we brought indoors to care for the disabled bees. Consequently it is actually equipped with two cameras, but we are only connecting up one. 

I decided for this box I would try and create something for a bee to really burrow down into if it wanted. So I took the top off an old olive oil bottle, cut it to shape and filled it with more of the small decorative stones. This would lie on its side at and angle, with the stones loose enough for burrowing (well, that's the plan). There's about 3 inches of "burrow length" in this little chamber.

"tunnel chamber"

 The plan, therefore, was to install this chamber inside the box then pack it tight all round with insulating material. BCW kindly went out and gathered some more moss and I also used a bit of our old hamster bedding to create a nice cosy chamber. The only open space is immediately in front of the lower camera, just to give is something to look at. Again, a tube extends from the entrance towards the back wall of the box. I also placed some aluminium foil down one wall to help with insulation. 


box 2 layouti

This box is going to be less protected from the elements than box 1 because it is going under our hive "shelter" which is not a tight fit - thus the wooden box will be exposed directly to the elements. Insulation is therefore paramount and so another layer of webbing goes across the top and then I topped this off with some more aluminium foil (not shown). 

insulating roof layer

Again, it is equipped with a thermometer in the central chamber. I really don't think a Queen could ask for a better winter residence! 

The completed set up

Here's a picture of the completed setup. Both boxes have been mounted in a North facing position, they are very sheltered and shady. So, from an environmental point of view, the main threat is cold/frost as they are not below ground. (Although, that threat still exists for a bee below ground to a degree.) 

our "hibernation station" alongside the beepol lodge

Over the course of the next few days we will monitor the temperatures in the box and check for thermal stability - i.e. demonstration that they are insulated from conditions outside and maintain a more consistent temperature. We will also check the effect of having the internal cameras (i.e. infra-red) on and off. 

If I'm honest, I'm not really expecting anything to use them, but I'd like to think that a bufftail (which loves to go underground) might at least give the fully-covered box a nosey. I'm really pleased with it - ok so the colours are a bit garish - but I think it has the makings of something that could just about convince a bumble to investigate. 

We don't quite know when our (or any) Queens will start looking to hibernate - it may be a month or more yet - it may be sooner. But at least we now have something to offer them if they are curious.




Lifting the Lid on things

I was home tonight, so it was the first chance to video our beehive in "action". I was home just in time to see a handful of baby workers heading out and back to the fields before they settled down for the night. 

Earlier in the day BCW had managed to catch a picture of a worker flying into the box.

worker bee entering nest box

Tonight we had to do a few things:


  • check the one-way flap into the box as we had seen bees trying to use it and apparently not succeeding
  • level the box properly with a spirit level to ensure there were no issues with the internal sugar water supply
  • insert a small thermometer so we can check the internal temperature of the box


Here's a video from when we took the lid off:

We were as quick and delicate as possible, conscious that the box would be cooling off with the lid off. I took the thermometer from our front nestbox for the timebeing and inserted the probe through the lid. 

When we replaced the box and opened the entrance we were amazed and delighted to see a single junior worker bee come out and inspect the lid! Brilliant! Here's the video of it doing so:

I can't believe how small the worker bees are - they are really tiny - the small ones only about 1 cm in length. We saw one resting on the wall earlier in the evening, warming up (the wall was well over 20 degrees C while the ambient temperature was about 14C).

My mind is already working overtime about how we are going to get a camera in this box, safely and with minimal anxiety to the bees. I'm thinking I'll have to do some kind of trial run too, to run through the basic moves and recovery plan if something goes wrong! 

It's a bit like a bank job in miniature!

Home, I'm Honey!

Today I also made a slight modification to the nestbox in the back garden to bring it up to a similar standard to the front nestbox. 

The changes/modifcations were as follows:


  • change internal tubing
  • add internal remote thermometer
  • add small capsule of honey-water (having seen this consumed with great gusto in the front nestbox by BB33)


The tubing change consisted of:


  • changing to white tubing from black to allow a little more light/translucency into the box
  • curving the tube to send the bee into the main body of the box
  • creating a hole in the tube below the camera so that we can positively confirm seeing the bee enter and exit the box


The box layout now looks like this:

new layout of rear nestboxYou can see the obvious new tubing layout and in the bottom right you can see the pen-lid filled with honey water. It is just gaffer-taped to the side of the box, which has proven to be a wholly adequate technique. The thermometer sensor is in the top right of the picture and runs to an external display unit a meter away. This LCD unit is actually suitable for embedding in a device or surface, so I may come up with some further ideas on where/how to mount it, if not in the box itself (e.g. it could be embedded in the box lid.)

We got chance to test the latest incarnation of the box out when I caught a bufftail (BB34) in the afternoon. 

Bb34 - Bufftail - rear nestbox

The new tubing system worked a treat and we could easily see her enter and leave the box. She went in the box for about an hour. She was quite placid with some mooching around and cleaning behaviour. Then after an hour she left of her own accord.

She didn't attempt to try the honey-water, so she obviously had other things to be getting on with!