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Saturday, 14 May 2011

Eurasian Tree Sparrows: Interesting Wiki-Facts

According to Wikipedia: "The untidy nest is composed of hay, grass, wool or other material and lined with feathers, which improve the thermal insulation. A complete nest consists of three layers; base, lining and dome. The typical clutch is five or six eggs, white to pale grey and heavily marked with spots, small blotches, or speckling; they are 20 x 14 mm in size and weigh 2.1 g, of which 7% is shell. The eggs are incubated by both parents for 12–13 days before the altricial, naked chicks hatch, and a further 15–18 days elapse before they fledge. Two or three broods may be raised each year; birds breeding in colonies produce more eggs and fledglings from their first broods than solitary pairs, but the reverse is true for second and third clutches. Females which copulate frequently tend to lay more eggs and have a shorter incubation time, so within-pair mating may be an indicator of the pairs' reproductive ability. There is a significant level of promiscuity; in a Hungarian study, more than 9% of chicks were sired by extra-pair males, and 20% of the broods contained at least one extra-pair young."

In my opinion the nest is not untidy, actually. I can confirm the three layers though. I can also confirm that both parents incubated the eggs. 15-18 days is quite a short period (it is ca. 3 weeks, i.e. 18-21 days with Tit hathclings). I cannot say how many eggs there were. I wonder if there will be a second clutch.

I found a couple of papers on Eurasian Tree Sparrows, so I might have some more to report soon.

Here some interesting links:

Friday, 13 May 2011

Eurasian Tree Sparrow Hatchlings!

There are at least 2 hatchlings in NB-1! I am so beyond happy, as I managed to catch a good glimpse of the two hungry hatchlings this afteroon. My last minute adaptations, i.e. side camera addition post-nest-building-completion, seem to have been successfull, and although I was not able to follow the egg laying process and the brooding in detail, I will be able to see the hatchlings develop afterall!

I guess the worm-transport last Sunday was already part of the feeding. By looking at the live stream they appear to be ca. 1.5 week old. However, the eyes are not open yet and they do not have many feathers on their heads. I heard chirping on Monday evening for the first time. I thus assumed that the eggs had hatched on Monday. If indeed there are only 2 hatchlings, these will grow (and will have grown) much faster than the 7+ Blue/Great Tit hatchlings. It takes Tit hatchlings ca. 3 weeks before they leave the nest, I am curious to see how long before the Sparrows take flight.


At work on Wednesday there were still 8 hatchlings alive though 2 were quite a bit smaller. I wish I could see how they are coming along. I hope they are still all there on Monday.

Thursday, 12 May 2011

Hatched Sparrows and 8 Blue Tits

On Friday when I left the office, there were still 8 Blue Tit hatchlings in NB-3. Two of them were quite a bit smaller than the others, but I hope they will make it through. One egg remains unhatched.

In NB-1, to my surprise, on Monday afternoon I heard tiny high-pitched chirping. I wonder when they hatched, I wonder how many they are. At any rate, both parents are quite busy with bringing food to the hatchlings. I caught a glimpse of one earlier today. They still appear to be featherless. So I suppose that they are less than one week old. However, they are quite noisy compared to the Tit hatchlings, which might lead one to think that they are older than they really are.

Sunday, 8 May 2011

Worm Transport into NB-1

09:46 am: One of the Tree Sparrows was inside the nest, the other flew to the entrance hole chirped and then flew to the tree. After some seconds, the Sparrow inside the nest left the nesting box. The second Sparrow flew to the nesting box and waited at the nesting box entrance hole with a big fat worm in its beak. It chirped a couple of times, looked around, chirped again and then flew in. So....? Was the male wanting to feed the female? Or was it the other way around? Or was it the male taking with himself a big fat worm to feed on whilst on duty in the nest, or was it the female? Or was it one of the parents just wanting to feed hatchlings? I do not think it is the latter, due to the fact that once in the nest the bird settled really quickly, no sound was/is to be heard and the feeding frequency seems to be too low, but perhaps I just missed a few.

09:52 am: The bird leaves the nest (flew into the tree) with no duty-replacement-bird and with nothing in its beak. (Outside temp: ca. 24°C in the sun already, ca. 14°C in the box)

10:00 am: A Sparrow enters the nest with soft nesting material in its beak, fixes a bit and settles in the nest (@ 10:06 still in nest). So no hatchlings.