1/6 #BOU2024 #SESH7

#ornithology #raptors #owls #urbanecology

1/6 #BOUsci23 #SESH7

Studying habitat selection year round is important because availability changes across the annual cycle!

Emerging research suggests selection is particularly weak during migration because individuals encounter a broader diversity of available resources

1/6 #BOU2023 #SESH7 The match/mismatch hypothesis (MMH) mainly focuses on the fitness consequences of asynchrony between consumers and the mean timing of the resource. Spatiotemporal variation in the resource peak height and width also influences the food available to consumers.

1/6 #BOU2023 #SESH7
#TropicalForests are the most biodiverse ecosystems on Earth. They are threatened by deforestation due to #anthropogenicalterations that may cause mass extinctions. So it is urgent to understand how forest loss affects #biodiversity and associated functions

3/6 #BOU2024 #SESH7
Data on occupancy, clutch size, brood size and fledgling success has been collected between 2011 and 2023 in Scotland from owls breeding in nestboxes. This data has been analysed in response to urban features such as building cover, ALAN and box-road distance.

4/6 #BOU2024 #SESH7
Occupancy was low in strongly built-up sites, but higher in sites near roads, especially the most artificially-illuminated ones. This indicates that sites near roads might be attractive as hunting grounds and ALAN might be exploited to find and catch prey.

6/6 #BOU2024 #SESH7
In summary, sites near roads and that are highly illuminated might be attractive for nesting and hunting. However, they appear to be low quality sites since breeding success is lower and thus they might represent ecological traps for the owls.

2/6 #BOU2024 #SESH7
Management of urban raptor populations requires to understand which features associated with urbanisation are decisive for maintaining their occupancy and breeding success. This study focuses on Tawny Owls, nocturnal raptors occurring in our woods and cities.

5/6 #BOU2024 #SESH7
Fledgling success was higher in sites far from roads and highly illuminated. Lower success near roads might be caused by reduced hunting efficiency due to traffic noise, while owls in further and quieter sites might be better at catching prey exploiting ALAN.

Sesh7! 3km + 1 km (cheating) - 173bpm. (In my defense gw tidur abis subuh tadi pagi) APPLAUSE

4/6 #BOU2023 #SESH7 We found the caterpillar peak height has a significant effect on the maximum fledged in the blue tit fitness function. The effect size was substantial, predicting a difference of up to 6 chicks per nest based on our range of caterpillar peak heights

#BOU2024 #Sesh7 . We found no evidence that ALAN impacted the remaining #health biomarkers measured in the study.

Health is a multivariate trait and can be difficult to quantify using only a few biomarkers. The more biomarkers you measure the greater understanding you have. (6/6)

3/6 #BOU2023 #SESH7 We estimated the timing, height and width of the caterpillar peak at each site by year (similarly to doi.org/10.32942/osf.i…). Caterpillar timing was used for each nests’ asynchrony, height/width were predictors of the equivalent for blue tit fitness.

#BOU2024 #Sesh7 . Preliminary Results! #greattits exposed to the ALAN had significantly lower SMI than the control group so were in poorer condition.
This could be due to the nestlings expending more energy at night with the parents unable to compensate with more food. (5/6)

2/6 #BOU2023 #SESH7 We have explored how the full phenological distribution of caterpillars affects the full phenological fitness function of blue tits using data from Phenoweb. We are using caterpillar abundance and the number fledged, conditional on at least one fledging.

4/6 #BOUsci23 #SESH7

We defined availability domain radii by estimating core home ranges areas for each season:
· Breeding: 5 km
· Migration: 50 km
· Stationary nonbreeding: 1 km

5/6 #BOUsci23 #SESH7

Contrary to predictions, selection was similar between scales

Selection was for treed areas during the nonbreeding stationary season and open areas during the breeding season

Selection was strongest during the breeding season and weakest during migration

#BOU2024 #Sesh7 . To look at the effects of ALAN on #health we quantified Scaled mass index (SMI), oxidative stress and corticosterone levels using morphological measurements and biological samples taken when the nestlings were 13 days old. (4/6)

3/6 #BOUsci23 #SESH7

We used GPS points in discrete choice models to understand roosting habitat selection during each stage of the year

We predicted selection would be determined by roosting attributes at the roost site scale and by other behaviours at the home range scale

9/9 #BOUsci23 #SESH7 Thank you for reading this thread!