Hole-nesting birds. In natural conditions great and blue tits breed in holes that are made by e.g. woodpeckers

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2 Hole-nesting birds In natural conditions great and blue tits breed in holes that are made by e.g. woodpeckers Norhern willow tits excavate their own holes in rotten trees and do not accept old holes or boxes In cultural habitats, most great and blue tits breed in nest boxes Hole-nesting birds are good study objects in ecology, since their nests are easy to find and monitor, and the boxes can be located in certain areas

3 Box/hole types Blue tit box - white colour - hole diameter 28 mm Great tit box - brown colour - hole diameter mm Willow tit box - excavated by the bird - natural or introduced rotten birch, alder, aspen, or even pine and spruce

4 University Study area

5 Identification in field Great tit, male song titityy song tityy alarm call Blue tit, male song 1 song 2 alarm call Willow tit song 1 song 2 alarm call Larger than blue tit, black stripe in yellow underside Blue colour in head, no belly stripe White underside, greyish brown back, black head

6 Sex-determination in field/hand Great tit - males have stronger belly stripe which broadens between the legs - an incubating female has a brood patch (underside skin soft and swollen, with great number of blood veins inside)

7 Sex-determination in field/hand Blue tit Sexes are almost similar looking Males are little brighter in colours (blue, yellow) Parents at nest can be sexed if you can directly compare them NOTE also, male sings! Colour banded individuals easy to sex due to sex-specific colours: Female: red, yellow, orange, white Male: blue, green, lightblue, lightgreen Neutral: Aluminium, white (i.e. white + orange = female, white + blue = male) IN ADDITION: only females have brood patch A male blue tit (therefore lightgreen band)

8 Sex-determination in field/hand Willow tit Sexes are similar looking Males are little larger in size; typically female wing < 63 mm male wing > 63 mm Note the brood patch, and that (mainly) only males sing! (no sex-specific colour bands like in blue tits)

9 The rings and colour bands The birds are marked for identification with one Aluminium (A or Al) ring and 1-3 colour bands (on tarsi) A-ring has a number code, which is the official identity of the bird Like V123456, J In field, the colour code is more useful Read from right (R) up to left (L) down, e.g. ARe/YeOr (Finnish: APun/KelOra) Shortcuts for other colours: Wh, Bl, Gr, Lg=lightgreen, Lb=lightblue (Finnish: Val, Sin, Vih, Vavi, Vasi) Be careful with R- and L-sides! R L a bird facing you

10 The rings and colour bands It is very important to find out the rings of birds in the beginning of breeding season colour bands: ad bird that has survived to breeding population only A-ring: a recruit from last summer no rings: unknown bird that must be caught and ringed The playback method playing the species songs/calls at the nest attracts the parents easier to read the colour bands

11 Age of blue and great tits Adult bird the same blue in primary coverts as in otherwhere in the wing Juvenile bird greyer blue in primary coverts than in otherwhere in the wing The above is for blue tit. The same difference in colour degree is applicaple to great tits, but the blue colour is a little bit more greyish (in both age classes)

12 BT: Ad BT:Juv

13 GT:Ad GT:Juv

14 Age of willow tits AD: more rounded tip in tail feathers; JUV: more pointed tip in tail feathers The pattern is similar in other tits, too NOTE, however! The differerence is not always clear!

15 Breeding season activities First signs of breeding are mosses that birds carry inside the box (moss nest, sammalpesä) Next they carry hair and feathers (hair nest, karvapesä) Soon 1st egg appear (start of breeding + egg laying period; pesinnän aloitus, muninta-aika) Only females incubate about two weeks (incubation period, haudonta-aika) Chicks hatch ±at the same time (hatching, kuoriutuminen) Both parents feed the young during nestling period (pesäpoikasaika) The nestlings are ringed at age of 13 days Finally the young leave the nest, ~day (fledging; lentoon lähtö, jonka jälkeen puhutaan lentopoikasista)

16 Empty box & female blue tit

17 Tits carry first mosses in the box moss nest

18 Hair nest including hair and feathers ready for egg-laying

19 First egg (blue tit) during egg-laying eggs are normally covered with hair and feathers

20 Nest during egg-laying looks like the hair nest because eggs are covered Checking the eggs carefully take the hair and feathers aside you can either feel the number of eggs with your fingers (1-3 eggs) or count them by looking to the opened nest cup cover the eggs afterwards

21 Nest with exceptionally few feathers and hair so few that the eggs are not covered (blue tit)

22 Full clutch which is incubated i.e. the clutch is open (blue tit)

23 Nests of other species Pied flycatcher - blue colour - no pigment Coal tit - similar to other tits Great tit - similar to other tits but greater One pied flycatcher egg among blue tit eggs

24 Birds inside the box Coal tit Blue tit Great tit Pied flycatcher

25 Calculating important dates Tits lay one egg per day (in bad conditions they can skip days!) Females start incubation after laying the last egg After days incubation period the chicks hatch in calculation we use 13 in early broods 14 is more probable So, if you found 7 eggs on 18.5., and incubating female with 10 eggs on (see the mid-row below) 1st egg was laid on (18 (7-1)) incubation started on (18 + (10-7)) chicks will hatch on 3.6. (21+13 = 34 May = 3 June) - sometimes, e.g. in early broods, somewhat later ( 4-5 June) Chicks will fledge at age of days (depending on species)

26 An example of a table of breeding parameters Clutch Hatching Brood Ringing Number of Nest Male Female 1st egg Size Day Size Day Fledglings Li17 A/valsin kelpun/a May 5 11 May 28 8 June 10 8 A/- -/- La4 A/sinsin -/Aora May 6 11 May June R4 -/- -/- May 6 10 lost R3 valvih/a -/- May 6 Overtaken by Pied Flycacher - Li17 parents were old friends from previous years - In La4 A/- indicates that male is a recruit from previous year, and was then caught during the breeding period and colour banded; Female is a new-comer to area - In R4 parents had no rings; the breeding attempt was destroyed during incubation period, and the birds remained unknown (no ringing, no measures) - R3 was overtaken by Pied flycatchers during egg-laying; female remained unknown

27 Blue tit female with newly hatched chicks

28 How to determine chick age? If you find a nest with nestlings without exact earlier information of the nest s timetable, the nestling age can be determined from colour (pink skin colour) pigment, i.e. the dark dots that appear when the feathers start growing in certain areas wing feather sheaths See the following examples

29 Newly hatched: Pink colour, no pigment, no feather sheaths, down can be wet

30 1 day: Skin colour, no pigment, no feather sheaths, down dry

31 2 days: Some pigment in back and wings, no clear feather sheaths in wings

32 3 days: Clear pigment in back and wings, small wing feather sheaths

33 4 days: Strong pigment = body feather sheaths, small wing feather sheaths

34 5 days: wing feather sheats longer

35 6 days: and longer

36 Researh activities during nestling period Ringing of unringed adults and nestlings + Morphological and condition measurements of parents and nestlings + Blood and feather samples Video recordings of nestling feeding parents Estimation of food resources by using frass fall -method

37 Activities on ringing day (day 13) Measurements Wing, tail, tarsus, body mass, (fat-score) DNA samples Drop of blood from wing vein of ad birds (or tail/wing feathers) Underside feathers of nestlings Feather colour samples (BT, GT) Some yellow breast feathers in small paper bags

38 Measurements and fat-score stages in birds Typical for parent birds

39 Video recordings Video recording method is applied for measuring the parental nestling feeding behaviour and the nestling diet The video camera is placed a few meters from nest entrance The camera records all feeding visits during a 90 min period, and the recordings can reveal The sex of parent (from colour bands, plumage) The quality of food (green caterpillar, non-green caterpillar, other prey item) The quantity of food (length of caterpillar)

40 Video recordings The movement of feeding parent must be stopped by using a stop-and-go system made of iron wire Video camera is placed 2-3 m from the nest (inside a plastic shelter) note sun position and background (do not direct towards sky) IMPORTANT! Stop-and-go system and dummy shelter must be placed a day before the recording so that the birds get used to them! When starting the recording, remember manual focus shutter speed to sport position time code in recording

41 Load size ~ caterpillar length Great tit compare to: 1) Bill lenght ca 1 cm 2) Hole diam. 3.5 cm 3) Tarsus ca 2 cm Note the caterpillar position 1 2 The caterpillar length ca 1.5 cm 3

42 Load size ~ caterpillar length Blue tit compare to: 1) Bill lenght ca 0.6 cm 2) Hole diam. 3 cm 3) Tarsus ca 1.5 cm Note the caterpillar position 1 2 The caterpillar length ca 1 cm 3

43 Load size examples - GT Green caterpillar 3 cm Other caterpillar 2 cm Green caterpillar 1.5 cm Other food eq. 0.5 cm

44 Green cat. 1 cm (note the curved position) Other cat. 1 cm Green cat. 1.5 cm Other cat. 1.5 cm Other cat. 2 cm Green cat. 1 cm (note the curved position) Other food eq. 1.5 cm (white butterfly difficult!) Other cat. 3.5 cm

45 Load size examples - BT Green cat. 1 cm Green cat. 2 cm Other cat. 2.5 cm Other cat. 2.5 cm

46 Estimation of food resources for breeding tits Moth and sawfly caterpillars feeding on tree leaves/needles are the most important food of nestling feeding tits Caterpillar abundance can be estimated by calculating their droppings (frass) falling under the tree canopy If we know the number and size of frass items fallen on a certain area, we can estimate the biomass of caterpillars By checking the frass fall in one week intervals, we can estimate temporal variation of food resources during the breeding period

47 Frass fall -method Plastic funnels of certain size (area) are attached in tree trunks most on Birch Betula spp., some on Pine, Spruce and Aspen The frass is gathered in a papered coffee filter filters are collected weekly frass is calculated and measured later in lab

48 Caterpillar biomass in birch by frass fall method in some years 0,9 Caterpillar biomass g/m2 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0, June Day