21/22. Climate Change and Adaptation

Expectation assuming no adaptation to compensate

100% loss of Manitoba breeding range

General shift in bird distributions

• Many bird species have shown a northward range expansion in recent decades

• An example is the non-migratory Northern Mockingbird

Bird distribution (breeding) results from 30 years of data

• Determine species distribution using BBS data in 1970 vs 2000

• Measure distance and direction of shift of southern species – i.e. they have room to move north

• Of 22 passerine species, 16 (73%) had a northward shift

• Median northward shift of these 16 species was ~100km

Christmas bird count data to estimate northward shift

• Study used Christmas Bird Count data to get overwintering/non-breeding distributions of 65 species songbird & woodpeckers

• Variable results, but most species showed latitudinal shifts north in winter range distribution + another great use of citizen science data!

• shifts differ by species and flyway

Great Tit timing response

• Year-round European resident,

• Average egg-laying date is 2 weeks earlier than in 1960s

• Shift in egg-laying date tracks increase in spring temperatures

Great Tit Plasticity

• For females that bred in multiple years, can assess how well each individual can track year to year changes in spring temperatures

• When spring was very warm, individuals could lay their eggs much earlier (remember this species is non-migratory)

• Females could also shift the other way, and lay eggs later in cold springs

• plasticity has increased over the decades

Bird most likely to adapt to climate change

Great Tit

3 migratory case studies for adjusting timing

1 - Pied Flycatcher

2 - Wood Thrush

3 - Purple Martin

Case Study 1

• Earlier springs and peak food but arrival date unchanged (this is a ‘phenotypic mismatch’) in Pied Flycatchers and caterpillar peak dates

Evidence of genetic change in Pied Flycatchers

• 2002 birds sourced from same population as in 1981 show earlier timing under identical lab conditions = conclude genetic evolution of timing

Case Study 2

• Re-tracked wood thrush

• Compared within- and between individual variation

Thrushes depart on almost the same day from year to year

Case Study 3

• Re-tracked individual purple martin migration timing (n=33)

• Repeat timing of egg laying (n=28,000)

• Compared within- and between individual variation

• migration highly variable at individual level

Migration repeatability

Highly variable across species and seasons

repeatability - measure of individual plasticity

Purple Martin population level timing of nesting

• birds lay earlier when its warmer

• birds fledge more young when they lay earlier

• shows plasticity

Purple Martin individual level timing of egg laying

Individual females laid their first egg earlier during warmer temps., or later with cooler temps.

i.e. high phenotypic plasticity

Do migratory birds have enough time to adjust?

• More northern breeders have less time between arrival and egg laying

• Timing of egg laying may be advancing faster than migration

Overall results of case studies

1 - No! Pied flycatcher spring arrival timing (but genetic evolution slower solution?)

2 - No! Wood thrush migration timing

3 - Maybe? Purple martin migration and nesting timing

=an active area of much needed research!

Risk of advanced spring timing

• earlier lay dates has risk of higher mortality with cooler temperatures in these days in Tree Swallow

• reports of new competition interactions among Pied Flycatchers in Great Tit nests