Foraging Habitat Preference And Habitat Use Of Lesser Spotted Woodpecker Dryobates Minor In Natural Secondary Forests

In order to investigate the foraging preference and habitat use of lesser spotted woodpeckers Dryobates minor in natural secondary forests,a survey was conducted at National Field Scientific Observation and Research Station of Maorshan Forest Ecosystem in Heilongjiang Province from March to June,2022.Lesser spotted woodpecker was tracked by quadrat combined with transect method and radio technology,and the quadrat was set to 20 m×20 m.Minimum Convex Polygons method was used to calculate home range.Bailey’s method based on utilization-availability,parametric test or non-parametric test were used to analyze foraging preference and nest site preference.Principal Component Analysis was used to summarize the main factors influencing the selection of foraging sites of the species,and correlation analysis was used to explore the sexes differences in main factors.134 foraging quadrats and 207 control quadrats were collected for foraging preference.Home range data were collected from 9 valid individuals,4 males and 5females,with an average of 175 locations per individual.27 nest site quadrats and 27 control quadrats were collected for nest site preference.The results are as follows:1.Lesser spotted woodpeckers preferred to use pecking to forage at the side branches or canopy of trees.Their single foraging time were concentrated within 9 min.They preferred to forage on trees about 15 m high,and they preferred to forage at a height of about 10 m.Living trees were their preferred foraging plant state.They chose Juglans mandshurica or Larix gmelinii as preferred foraging tree species.The dominant species that they preferred to forage were Ulmus davidiana or Juglans mandshurica.Lesser spotted woodpeckers preferred to forage in natural conifer and broad-leaved mixed forest.They selected flat slope or southwest slope area as preferred foraging habitat.They preferred to forage on the habitat where the density of semi-dead wood,snag,log and crown(41±21%)were lower and the distance from nearest human disturbance was closer.The main factors influencing the selection of foraging habitats of lesser spotted woodpeckers were tree density,foraging plant height,slope,dominant species,distance from nearest human disturbance,and mean tree height in quadrats.Females preferred to forage on the middle upper part of the tree and in the habitat with the density of about 50 trees.Males preferred to forage in the canopy of tree(P<0.001),lower bush or stems of dead herbaceous plants(P<0.001),and in the habitat with the density of 20-60 trees(P<0.05).2.The total home range of lesser spotted woodpecker was 2.396±0.688 km~2.There were significant differences between the home range before(2.901±1.354 km~2)and during breeding period(0.482±0.275 km~2,P<0.01),and between before and after breeding period(0.617±0.335 km~2,P=0.01)respectively.There was no significant difference between the home range during and after breeding period(P=0.95).There was no significant difference of the home range between sexes(Total,P=0.792,before,P=0.659,during,P=0.287,after,P=0.554).3.Lesser spotted woodpeckers built new nests only during breeding period,and old nests were reused during non-breeding period.They had no preference for nest tree species but avoided roosting on Larix gmelinii or Pinus koraiensis.They preferred to roost on snags.The trees were used for nesting had bark coverage of about 90%,height of about 7.7 m and diameter at breast height of15-20 cm.Nest height was about 4.8 m,and the nest was located in the trunk and middle upper part of the tree.Nest height increased with the increase of nest tree height and nearest branch distance.Nests mainly faced south(33%).They preferred to nest in the natural conifer and broad-leaved mixed forest with a lower density of semi-dead wood,the density of about 4 snags and a lower crown density(46±3%).It is suggested that keep dead trees with low density and low degree of decay in the unit area(0.04 ha),and maintain 40-45%crown density and about 50 trees density,and stay the forest type of the natural conifer and broad-leaved mixed forest to protect the population and habitat of lesser spotted woodpeckers.