I prepared this short report for the City of Kamloops in consideration of their cooperation in allowing us to access the landfill and sewage lagoons during our annual Christmas Bird Count. I thought I would share it with the club and other readers. I don’t know if the long horizontal table will ultimately fit or website format but here is an attempt.

Photo of juvenile Glaucous Gull with Herring Gulls at landfill.

Executive Summary

Surveys at the Kamloops municipal landfill during the mid-December period over a span of 25 years resulted in 15 species and a cumulative total of 39943 individual birds being recorded. All but one of the species are able to consume both meat and vegetal scraps for much of their diet which is available as putrescible waste at the landfill. Horned lark is the lone species and individuals are largely seed eaters in the winter and may only be searching for grit on the open ground as opposed to food waste. The site is the single largest attraction for gulls, corvids and starlings in the Kamloops area.

Introduction

Annually since 1984, Members of the Kamloops Naturalists have conducted an official Audubon Christmas Bird Count in the Kamloops area. The mission Flats area has been counted each year, but starting in 1993, a small core of members coordinated by the author has been granted official access to the Kamloops Landfill for a short period to count birds feeding on putrescible waste. This has added immensely to our database of species that occur in the area but remain undetectable from public areas. The general time period for the count is a 2 week window beginning about mid-December and ending in early January, depending upon the occurrence of weekends in any particular year. Except for one count taken on 02 January, all of the 25 counts were taken the week of  14 – 21 December throughout the period of 1993 – 2017.

Methods

 A team of 2-3 observers entered the commercial area of the landfill where fresh garbage was being deposited. All counts were undertaken on weekends due to the lack of observers available to conduct the larger count during the week. The lack of fresh curbside and restaurant waste compared to weekdays is acknowledged as a limitation to the survey. Wearing hi-vis gear, the observers avoided the heavy machinery and conducted species counts from safe vantage points. Total survey time was generally no more than 60 minutes. Because eagles, gulls and ravens spend considerable amounts of time at the landfill, flying near the landfill and roosting along Mission Flats, species counts included birds away from but near the landfill. These birds most certainly spend part of their time foraging in the landfill. Observations were made with binoculars and telescopes with at least one observer considered to be highly-skilled at identifying the various species. The author was present during all surveys.

Summary of Kamloops Landfill CBC data  

Species Diversity

The species listed in Table 1  (click on the above link to a pdf file) were counted during the Christmas Bird Count on the 25 dates listed in the table. They represent a 1 hour count on a single day each year. Note that gull and eagle numbers include birds roosting on the mud flats or in nearby trees, but all undoubtedly utilize the landfill as a food source at some time during the day, even if all birds were not observed feeding at the landfill during the one hour census. Our data collection methods did not separate river mud flat birds from those in the landfill but routine flights between the 2 locations were observed such that the numbers represent the total population in the area.

It should also be noted that the numbers in the preceding table were obtained during weekend censuses due to the logistics of conducting the overall Christmas Bird Count. Discussions with landfill personnel suggest that eagle numbers in particular may be higher during weekdays when municipal trucks bring more waste from collections around the city neighbourhoods and volumes are much greater than on weekends when fresh waste is dumped in much smaller quantities. A separate eagle census during mid – January usually produces significantly more birds then the mid – December census.

Table 2 summarizes the number of species and individuals for the 25 years of surveys up to 2017. The total number of species detected over the survey period was 15 (n=25) with a range of 3 – 14 in any particular year. The mean number of species per survey was 9.8

The number of individuals ranged from 386 – 3784 on any one survey, with the total number of individuals tallied being 39943 (n=25) with a mean of 1598 individuals per survey.

Species & Individuals Summary Table 2
Date	Total Species	Total Individuals
1993-12-19	3	501
1994-12-17	13	1206
1995-12-17	8	707
1996-12-22	6	320
1997-12-21	6	414
1998-12-20	9	1452
1999-12-19	11	819
2000-12-16	14	1612
2001-12-15	13	1456
2002-12-15	12	3405
2003-12-21	11	2621
2004-12-19	11	1947
2005-12-18	12	3505
2006-12-17	9	1635
2007-12-16	13	3017
2008-12-14	9	1667
2009-12-20	8	771
2011-01-02	8	1909
2011-12-18	11	386
2012-12-16	11	1606
2013-12-22	9	3784
2014-12-21	11	1485
2015-12-19	11	2519
2016-12-17	8	1109
2017-12-17	9	1400

Common ravens and European starlings were the only species found on 100% of the surveys although bald eagles were no doubt present at the landfill during all survey periods but were simply not observed during the survey times on two occasions. Bald eagles, herring gulls, American crows and Brewer’s blackbird were the next most frequently observed species. Table 4 ranks the 15 species by frequency of occurrence. Ten species were found on more than 60% of all counts while 5 species were found on less than 30% of the counts. These latter species represent birds that occur infrequently during the winter in the Kamloops area generally, with the 4 gull species often frequenting landfill sites when they do occur in the interior. Horned larks do best in areas of low snowfall or cleared ground which is always present at the landfill due to vehicular disturbance. The larks do not seem to feed on putrescible garbage.

 

 

Frequency of Species Occurrences Table 3
Species	# Occurrences	% of Surveys
Ring-billed Gull	19	76
California Gull	7	25
Herring Gull	20	80
Lesser Black-backed Gull	1	4
Iceland (Thayer’s) Gull	6	24
Glaucous-winged Gull	16	64
Glaucous Gull	4	16
Bald Eagle adult	23	92
Bald Eagle sub-adult	15	60
Black-billed Magpie	17	68
American Crow	20	80
Common Raven	25	100
Horned Lark	6	24
European Starling	25	100
Red-winged Blackbird	19	76
Brewer’s Blackbird	23	92

 

 

 

Frequency of Occurrence Ranking Table 4
Frequency of Occurrence in %	Species
100	common raven, European starling
90-100	bald eagle, Brewer’s blackbird
80-90	herring gull, American crow
70-80	ring-billed gull, redwinged blackbird
60-70	glaucous-winged gull, black-billed magpie
50-60
40-50
30-40
20-30	California gull, Iceland gull, horned lark
10-20	glaucous gull
0-10	lesser black-backed gull

 

 

 

 

 

 

Species Ranked by Cumulative # of Individuals Table 5
Species	Cumulative Individuals	Avg	Rank Order
European Starling	31745	1269.8	1
Common Raven	5425	217	2
Herring Gull	1223	48.9	3
Brewer’s Blackbird	962	38.5	4
Ring-billed Gull	710	28.4	5
American Crow	387	15.5	6
California Gull	258	10.3	7
Bald Eagle	242	9.7	8
Red-winged Blackbird	167	6.7	9
Glaucous-winged Gull	73	2.9	10
Black-billed Magpie	70	2.8	11
Horned Lark	44	1.8	12
Iceland (Thayer’s ) Gull	11	0.5	13
Glaucous Gull	4	0.2	14
Lesser Black-backed Gull	1	0.04	15

 

Table 5 ranks the species by the cumulative number of individuals observed over the 25 year survey period. European starlings were consistently the most abundant bird but numbers were approximate due to the difficulty in obtaining an accurate count. The birds moved frequently and re-assembled into ever changing groups and were often flushed by the trash-compacting machine making it difficult to maintain a consistent count of so many individuals. The real numbers were likely higher. Common ravens were the next most abundant species, with the landfill being a significant attraction during the winter months when natural food sources are less available.

The average was obtained by dividing the number of individuals by 25 surveys.

Conclusions

The Kamloops municipal landfill is a significant source of food for a variety of gulls, corvids, starlings  and bald eagles during the winter months. Without this food being available, the numbers of these species would undoubtedly be reduced in the Kamloops area. Several other species also utilize the site but also find other food sources nearby, but the landfill provides major supplementary feeding.