Importance of old coniferous habitat on Black-backed

Woodpecker nestling growth in unburned boreal forests Junior A. Tremblay1, Jacques Ibarzabal2, Jean-Pierre L. Savard1

1Environnement Canada 2Université du Québec à Chicoutimi

• We calculated the growth rate (K; Ricklefs 1967) of the truncated logistic

growth curve of 4 physical characteristics.

• Only data from nestlings that survived to fledging were used for the

analyses of nestling growth.

• Amount of old coniferous habitat was estimated in each breeding home

range, based on Tremblay et al. (2009).

• We used mixed effect generalised linear models (lmer4 package (Bates et

al. 2014) in R; Core Team 2013).

• Full model: Kcharacteristic1 ~ order of hatching of the nestlings + amount of

old coniferous habitat in the home range + (1|nest) + ε

• Null model: Kcharacteristic1 ~ order of hatching of the nestlings + (1|nest) + ε

• Full and null models for each physical characteristic were evaluated

using the Akaike’s Information Criterion (AIC) (Burnham and Anderson 2002).

CONTEXT

METHODS

RESULTS

DISCUSSION

• The Black-backed Woodpecker breeds successfully in unburned forests (Goggans et

al. 1989, Bonnot et al. 2008, Tremblay 2009, Craig 2013) which are considered as a sub-optimal

habitat (Hutto 1995, Murphy and Lehnhausen 1998, Nappi and Drapeau 2009).

• It has been suggested that the species requires a minimal amount of old forests to

breed succesfully in the eastern boreal forest (Tremblay et al. 2009).

• Nest success is often used to evaluate the impact of environmental stressors on

the species fitness (Deng and Gao 2005, Smith and Smith 2013).

• Nestling growth could be a sensitive tool to detect subtle reductions to species

fitness and investigate habitat/fitness relationships.

• We monitored Black-backed Woodpecker nestling growth in unburned boreal

forests under the influence of commercial logging and investigated the importance

of old coniferous habitat on Black-backed Woodpecker nestling growth.

• Hypothesis: The amount of old coniferous habitat in the home range of Black-

backed Woodpecker increases nestling growth rate of weight, enhancing the

parent’s fitness.

2. Four physical characteristics

1. Accessing the nestlings (Ibarzabal and Tremblay 2006)

3. Statistical Analysis

STUDY AREA

Nest

Bates, D., M. Maechler, B. Bolker and S. Walker, 2014. http://lme4.r-forge.r-project.org/. Bonnot, T.W., M.A. Rumble and J.J. Millspaugh, 2008. The Condor 110: 450-457. Burnham, K.P. and D.R. Anderson, 2002. Springer-Verlag (Publisher). Craig,

C. 2013. Master Thesis, Acadia University. Deng, W.-H. and W. Gao, 2005. Biological Conservation 126: 363-370. Goggans, R., R. D. Dixon and L. C. Seminara, 1989. Technical Report 87-3-02. USDA Deschutes National, Oregon. Hutto, R.L.,

1995. Conservation Biology 9: 1041-1058. Ibarzabal, J. and J.A. Tremblay, 2006. Ann. Zool. Fennici 43: 235-238. Murphy, E.C. and W.A. Lehnhausen, 1998. The Journal of Wildlife Management 62: 1359–1372. Nappi, A. and P. Drapeau, 2009.

Biological Conservation 142: 1381-1391. R Core Team, 2013. http://www.R-project.org. Ricklefs, R.E., 1967. Ecology 48: 978-980. Smith, K.W. and L. Smith, 2013. Bird Study 60: 169-175. Tremblay, J.A., 2009. PhD Thesis, Université du Québec à

Chicoutimi. Tremblay, J.A., J. Ibarzabal and J.-P.L. Savard, 2009. http://www.ace-eco.org/vol4/iss1/art2/

Weight (g) Tarsus length (cm) Culmen length (cm) Wing length (cm)

• As expected, the amount of old coniferous habitat influenced positively

the growth rate of weight of Black-backed Woodpecker nestlings and

did not influence the growth rate of the other physical characteristics.

• This may be explained by the fact that old coniferous habitat contains ≥

40% more deadwood volume (m3/ha) than other habitats in the study

area, offering more suitable habitats to forage (Tremblay et al. 2009),

increasing provision of food to nestlings by the parents.

• Our results suggest that Black-backed Woodpecker fitness may be

affected by the reduction of old coniferous habitat in forest managed

landscapes.

• We suggest that the use of nestling growth may constitute an interesting

avenue for future habitat/fitness studies.

Figure 1. Progression with days after hatching of the culmen (cm), tarsus (cm), weight (g) and wing (cm) in

13 Black-backed Woodpecker nestlings from 5 nests (orange triangle, green square, red diamond, blue

circle and X; the first hatching nestling is an empty character, the second is a full one and the third has

stripped one).

Table 1. Mixed effect generalised linear models of the growth rate (K) of the truncated logistic growth curve in 13

Black-backed Woodpecker nestlings (5 nests; 4 physical characteristics) in relation to the amount of old coniferous

habitat in each breeding home range on 4 physical characteristics (∆AIC are the comparison of the full model with

the null model).

0

10

20

30

40

50

60

70

80

0 4 8 12 16 20 24

We

igth

(g

)

Days

0

20

40

60

80

100

120

0 4 8 12 16 20 24

Win

g (

cm

)

Days

0

5

10

15

20

25

30

0 4 8 12 16 20 24

Cu

lme

n (

cm

)

Days

0

5

10

15

20

25

30

0 4 8 12 16 20 24

Ta

rsu

s (

cm

)

Days

ACKNOWLEDGEMENTS

This work was supported by the Consortium de Recherche sur la Forêt Boréale

(Université du Québec à Chicoutimi) and the ministère des Ressources Naturelles du

Québec. We thank Abititi-Bowater Inc. for their logistical support, and S. Boily, C. Buidin,

P. Desmeules, M. Huot, L. Morin and Y. Rochepault for their help in the field. Finally, we

thank Scott Wilson for his statistical assistance.