...Going Crazy with Nesting Box Contruction...

...needless to say, I have now installed a second camera in a second nesting box (the nesting box I removed on the last weekend in February)...

The set up is somewhat different this time: a different camera (colour this time), and instead of making a hole from the top through the roof of the nesting box, I made use of the big chunk of material under the roof by making a hole and placing the camera in it, thus reducing leakage problems.



Here are some technical details of the camera:
Description: 8,47 mm (1/3") CMOS Farb-Kamera mit 6 mm Lens
Voltage: 9 V/DC
Resolution: 250 920 Pixel
Current: 150 mA
Resolution (Lines): 280
Optical Resolution: 510 x 492 Pixel
Light Sensitivity: 3 lx
Aperture Settings: Yes
IR-Light: Yes
Integrated Optical Zoom: No
Integrated Microphone: Yes
Dimensions: (L x W x H) 55 x 38 x 25 mm

Motion Detected!

Latest image from this morning captured by the motion detection system of the newly acquired video server!

Visit Statistics

I have a partial result in terms of visit-statistics and have posted two plots here.
The first plot depicts the number of visits made by each species on a particular day. The second plot depicts the number of visits made one or more Eurasian Tree Sparrow(s) per hour each day (the images can be enlarged by clicking on them).

Obvious is the increase subsequent to the beginning of nesting (09.03.2010) and well that since nesting, the other two bird species have visited less frequently if not at all. Visits made by the Sparrow after the midday day hours were all made post 9th of March, i.e. beginning of nesting (I defined this as the date on which the Sparrow brought the first twigs in the box, "heavy" nesting actually began on the 15th of March)

Blue Tit Frequencies

It is taking me longer than expected to complete the statistics regarding the number of visits per day per species, so I have decided to post a frequency analysis of the blue tit's chirping, as expected the peak frequencies are higher than both the Sparrow and Great Tit.



A skeptic asked me how reliable the frequencies are that I have posted...in reply I have examined two different chirpings (in which of course the bird is doing more or less the same thing) of the blue tit and have plotted them in the graph below. I think one can say that one plot is fairly representative, given of course that I am mostly interested in a qualitative analysis rather than a quantitative one. So unless specifically requested I shall not (at least not in the near future, though it might be quite interesting) indulge in a frequency-spectrum spreading.



Also interesting is the comparison between the results obtained from a single chirp (1 and 3) and those obtained for a longer period of time (4) as certain frequencies develop narrow peaks.

Successfull Display?

Despite yesterday's Kamin Day, the nesting box was visited. A Eurasian Tree Sparrow entered box a couple of times during the mid-morning.

I have the feeling that this was not our now familiar constructer but a meticulous inspector. I am wondering if it was a female that inspected the box.

You may judge for yourself by looking at the video below…and let me know what you think!

Frequency Spectra: Sparrow vs. Great Tit

As promised I fed the audio files of the two displays (dated 2010.03.12 and 2010.03.13) to audacity to compare the frequencies used by the two different species (Eurasian Tree Sparrow and Great Tit). As expected there are clear differences. The figure below (click to enlarge) depicts frequencies and normalised dB levels (to remove the dependency on microphone settings). The images below the plot (colour coded for the two birds: blue = Sparrow, read = Great Tit) are the waveforms.



Also interesting is the comparison between the chirping frequencies during the display and during "nesting" as I call it. Below is a plot comparing these for the Eurasian Tree Sparrow (12.03.2010 = Display; 17.03.2010 = Nesting)



It appears that during the display, the male bird does add colour to its singing by increasing the relative importance of the higher frequencies. Unfortunately, I do not have nesting sounds from the Great Tit, so I cannot perform a direct comparison. I will thus have to look this up to see if I can find any backing.

2010.03.17 Eurasian Tree Sparrow Nesting

..some more nesting...