A specialist predator in a food web with cyclic alternative prey: The gyrfalcon-ptarmigan case revisited

Population dynamics of specialist predators are tightly linked to their main prey and can in simple food webs, lead to complex predator-prey interactions (e.g., predator-prey cycles). However, the strength of these interactions may be affected by the availability of alternative prey if it appears in high numbers and the predator's diet is sufficiently flexible. A prominent example of a specialist predator-prey interaction is the interaction between gyrfalcon and ptarmigan known from simple food webs with few alternative prey. Here we use 23-year long time series from a more complex food web in northern Fennoscandia to investigate the relative roles of main (ptarmigan) and cyclically fluctuating alternative prey (lemmings) in driving gyrfalcon nesting territory occupancy and production of young. We find that nesting territory occupancy dynamics are dependent on both main and alternative prey, while fledgling production within occupied territories is independent of prey abundance dynamics..., , # Data from: A specialist predator in a food web with cyclic alternative prey: The gyrfalcon-ptarmigan case revisited

Dataset DOI: [10.5061/dryad.jdfn2z3nn](10.5061/dryad.jdfn2z3nn)

## Description of the data and file structure

Here we provide data and code to replicate the study \"A specialist predator in a food web with cyclic alternative prey: The gyrfalcon-ptarmigan case revisited\". The dataset include a 23 years of monitoring data on 34 gyrfalcon nesting territories and an equally long snap-trapping time series on Norwegian lemming from Finnmark in Northern Norway. It also include scripts to run analysis of driver of occupancy dynamics of nesting territories and territory productivity. 

### Files and variables

#### File: 0_jagsmodel.R

**Description:** Define the näive dynamic occupancy model used to investigate drivers of occupancy dynamics in gyrfalcon nesting territorier

#### File: 0_productivity_normalregression.R

**Description:** Code to run the productivity analysis.

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