Friday, 14 December 2012

Warsaw Swift tower is up!

We previously reported on a design competition for a Swift tower in Warsaw, which was won by Menthol Architects. Since then we have been pleased to be asked for our opinions on detailed aspects of the implementation.

Rafal Pieszco writes: 

Click picture to enlarge
We have completed works on the construction and installation of the swift tower, therefore the first free-standing tower for swifts in Poland is up! On Monday, Dec. 17, at 12.00 in the park at Odkryta street (Warsaw, Białołeka), a press briefing will be held related to the completion of the investment.

The structure is 8 meters high and its shape refers to the silhouette of the flying swift. Why swifts arouse so much emotion? Well, they are irreplaceable, and above all, a natural weapon against the mosquitoes and biting flies. During the day, one swift can eat up to 20 thousand of these troublesome insects. 

For the complete story see here

Thursday, 6 December 2012

Michael Osborne's Swift Hotel

UPDATE August 2013: Michael succeeded in attracting Swifts into 3 of his boxes, of which one pair settled in the top box on the right. Michael had used black paint below the entrances on all 3 boxes that the Swifts entered

It is good to see some considerable effort put into the architectural form of a structure built for Swifts. Our Victorian ancestors got the hang of it with their elegant dovecotes. More recently, the Americans have a whole industry using creative designs for Purple Martin houses. It is desirable that accommodation for Swifts not only suits the birds, but also that it enhances the architectural forms in our environment. Of course, Swift accommodation may be more challenging, as it needs to be erected at least 5 metres high, but Michael Osborne has shown here what can be achieved on the gable end of a modest house.

Here is a picture, left, of Michael's complete 'hotel', which is installed on his girlfriend Amy's house. And my, what an improvement to an otherwise bland gable end.

This birdhouse contains 8 nest chambers for Swifts, it is constructed out of marine ply, and all cut ends are sealed so they are permanently waterproof.

The internal structure is quite complicated, so the following Google Sketchup drawings are intended to illustrate how it goes together.

Sketchup model of complete box

There are 2 sets of 4 boxes each, 4 with their entrances under the louvres on the front and 4 with their entrances on the right. There are no entrances on the left. 

For illustrative purposes, we have chosen a sun angle that highlights the relief of the box, in practice it is installed facing away from the sun.

Front assembly removed

In this picture on the left, the entrances to the 4 boxes on the right can be seen in the 4 floors.

The space under the roof, behind the decorative grill can be used to house speakers to play attraction calls.

Most cuts in this design are at 15°, so relatively easy to make with a jigsaw.

View from inside of front assembly
The front assembly shows the 4 entrances to the boxes on the left side of the box (when viewed from the front).

Should anyone wish to create something similar, then MIchael is happy to supply the Google Sketchup model so you can read off the dimensions.

For many more pictures of this 'hotel' under construction, see SMSWW (requires login).

Saturday, 1 December 2012

Car batteries and solar panels

[We have now consolidated everything on attraction calls on this page]

There are some situations where there is no mains power, in which case, the only alternative is a battery, possibly backed up with a solar panel.

Contributed by Dick

There are commercially available bird call systems to solve this problem, for example based upon the Martley Electronics Bird Scarer and the Spark4 Birdsong Player. There is nothing wrong with these systems, except they are probably overkill for a Swift attraction call player, and cost more than you might wish to pay.

We have been exploring the use of a solar panel to recharge a car battery which then powers a Cheng Sheng player amplifier system. At maximum volume, it consumes half an amp at 12 volts (6 watts). At a more reasonable volume it consumes about 0.3 amps (~4watts).

Thus, a car battery of, say, 45 amp-hours could provide 150 hours of continuous running before the battery becomes flat. It is probably not a good idea to run a battery completely flat. However using half its capacity would provide 75 hours. At 4 hours per day, it would run for nearly 19 days.

Such an approach might be workable, recharging the battery every 19 days, longer if you use a bigger battery. This is barely practical if the battery is in a remote location, such as the top of a church belfry (we've tried it), in which case the addition of a solar panel should be considered.

Schematic showing component connections

As the Cheng Sheng player amp consumes up to 6 watts, we bought a 20 watt xm solar panel (costing £30) and a Morningstar SunGuard 4.5A solar regulator (costing £28) from Midsummer Energy in Cambridge, and we used an old car battery which still had about 25 amp-hours capacity. We used a 12 volt digital timer (see here) to limit the playing to 8 hours a day and it has been running successfully (in winter!) for 40 days without the battery going flat [it finally went flat after 50 days on 23rd December after a week of cloud].

It is worth taking some trouble to mount the solar panel at the optimum direction towards the sun. We reckon that, for the period 21 May to 21 July (the main Swift attracting season, one month each side of mid-summer's day), facing south, with the plane of the panel at 35° to the horizontal is about right (the latitude of Cambridge is about 52°N). See here for a useful sun-angle calculator.

For an alternative 12 volt timer, we have tried DC 12V Digital LCD Power Programmable Timer Time Switch Relay 16A. it requires some wiring up, but is a low price and seems to work well. It is also available on Amazon.