DOI: 10.5061/dryad.2jm63xt05
title: Data from: The thick-billed murre (Uria lomvia) in Northwest Greenland (Avanersuaq) relies on Arctic cod (Boreogadus saida) in a changing climate

description: Considering seabirds as indicators of environmental change, we compared
 thick-billed murre (Uria lomvia) adult and chick diet in the North Water
 polynya region (NOW), NW Greenland, during 1997 and 2023. In the adult
 murre diet, fish accounted for 86% and 42% of food items by number and 90%
 and 99% by wet mass (WM) in 1997 and 2023, respectively. Arctic cod
 (Boreogadus saida) was the most important prey, contributing 90% and 99%
 of WM in 1997 and 2023, respectively. In 1997 the murres ate mostly small
 1-year old cod but in 2023 they mainly took larger 2- and 3-year old
 Arctic cod. In the chick diet, gadids contributed 71% and 86% of prey
 items brought to the chicks in 1997 and 2023, respectively, supplemented
 by sculpins and eelpouts in 1997. Capelin (Mallotus villosus) increasingly
 occur in the area but did not appear in the murre diet. The study
 highlights a consistent reliance on Arctic cod, although with differences
 between sampling years in size of ingested specimens. We recommend
 continued monitoring of top predator diets, coupled with local knowledge,
 to understand the impacts of ongoing changes in the region.
description: # The thick-billed murre (Uria lomvia) in Northwest Greenland (Avanersuaq)
 relies on Arctic cod (Boreogadus saida) in a changing climate
 [https://doi.org/10.5061/dryad.2jm63xt05](https://doi.org/10.5061/dryad.2jm63xt05) ## Description of the data and file structure Stomach contents of thick-billed murres (*Uria lomvia*) collected in Northwest Greenland – 40 birds from 1997 and 40 from 2023 – were analyzed according to the methods described in the journal article. See sampling locations in Figure 1 of the journal article. ### Files and variables #### File: Prey\_items\_identified\_in\_NW\_Greenland\_Thick-billed\_Murre\_stomachs\_1997-2023.csv Description: Identification of stomach contents of Thick-billed Murres (*Uria lomvia*) in Northwest Greenland 1997 and 2023 ##### Variables * Raw data for journal article published in Arctic Science, data pooled for proventriculos and gizzard: Coll_Date        Collection date Bird_ID            Unique identifier of each sampled bird Sex                   Sex of the collected murre ItemType        Type of item - fish, invertebrate, parasite, non-food Prey_Species  Identified prey species No_of_prey     Number of prey items SL (cm)            Standard Length (SL) of prey item  (cell value ‘null’ indicate not measured) WM (g)            Estimated total Wet Mass (WM) (g) of the prey items #### File: Boreogadus\_saida\_otolith\_size\_in\_NW\_Greenland\_Thick-billed\_Murre\_stomachs\_1997-2023.csv **Description:** Measurements of *Boreogadus saida* otoliths from stomach contents of Thick-billed Murres (*Uria lomvia*) in Northwest Greenland 1997 and 2023 ##### Variables * Raw data for journal article published in Arctic Science: Coll_Date        Collection date Coll_Year         Collection year Coll_Month     Collection month Sex                   Sex of the collected murre Stomach          Stomach section: P= proventriculos, G= Gizzard Prey_Species  Identified prey species OL (mm)          Otolith lenght (mm) SL (cm)             Standard Length (SL) of B. saida according to equation SL = (OL*1.897)+2.3862 WM (g)             Prey Wet Mass (WM) (g) of B. saida according to equation WM = (0.0046*SL^3.24)