Saturday 21st December 2024

 

Winter solstice on a cool dull drizzly morning. 420 Cormorant went out fishing. Offshore movements very poor with a handful of Red-throated Diver going either way & 9 Kitts pulling in behind Stenna going out. Heading south 3 Brent, Oyk & Shelduck exemplifying how little is presently on the move. Rock Pipit & Turnstone on the point.

Friday 20th December 2024

 

303 Cormorant headed out in the half light early on a frosty morning. Rock Pipit on the point, otherwise just the residents.

Migratory movements of bats are shaped by barrier effects, sex-biased timing and the adaptive use of winds

 Migratory movements of bats are shaped by barrier effects, sex-biased timing and the adaptive use of winds

For those interested in bat migration, which we have been involved with, have just received the below from Sander in The Netherlands :-

We just published a paper in Movement Ecology on bat migratory movements in the southern North Sea area.

 

How ecological barriers like the North Sea affect bat migratory movements is still poorly known. In 2021 and 2022 we tagged 44 Nathusius’ pipistrelles (Pipistrellus nathusii) on the East coast of the United Kingdom (UK) and investigated their movements to continental Europe using the MOTUS Wildlife Tracking System.

 

Our study demonstrates that bat migratory movements are highly influenced by barrier effects, sex-biased timing of migration and the adaptive use of winds.

➡️ Barrier effects cause migratory movements along the coast, and crossings over sea are shortened by deviating from the general migration direction.

➡️ In spring males migrate later in the season than females.

➡️ The overall migration speed of females was 61 km/day, and 88 km/day after their last detection in the UK

➡️ Bats use wind adaptively to reduce airspeed when flying under tailwind and increase airspeed when flying under crosswind conditions.

➡️ Departures over sea coincidence with tailwinds, enabling bats to more than double their airspeed, reaching groundspeeds of up to 16.8 m/s (60.5 km/h).

➡️ Our analysis suggests that bats select altitudes with favourable wind conditions and that they seek altitudes of several hundred meters, possibly extending up to 2,500 m.

➡️ Low-altitude migration occurs when wind conditions are less favourable , e.g. during generally low wind speeds and in response to increasing headwinds or crosswinds at higher altitudes.

 

To our best knowledge this is the first study to estimate flight altitudes using 2 D tracking data.   

 

The results of our study contribute to a more comprehensive understanding of the decision-making process and adaptations bats employ during their migration.
Elucidating bat migration patterns will enable us to develop effective conservation measures, for example in relation to the development and operation of coastal and offshore wind farms.

 

You can access the paper here https://lnkd.in/gePCDPFU.

 

We dedicated this paper to the memory of Ommo Hüppop, who co-authored this paper.

 

Kind regards,

Sander Lagerveld, Pepijn de Vries, Jane Harris, Sue Parsons, Elisabeth Debusschere, Vera Brust and Heiko Schmaljohann

The paper can also be accessed by copying & pasting this to your search engine -

https://movementecologyjournal.biomedcentral.com/articles/10.1186/s40462-024-00520-7

Thursday 19th December 2024

 

Very predictable selection with next to nothing on the move. Just the regulars on the reserve including 3 Cetti's. A first-winter Caspian Gull dropped in briefly & 9 Common Scoter sat offshore are worth a mention.

Wednesday 18th December 2024

 

270 Cormorant went out fishing early on a mild windy morning Southbound 19 Golden Plover, 11 Common Gull, 7 Turnstone, 5 Brent & a Knot with northbound a Brent & a Gannet. Rock Pipit & Turnstone on the point & 7 Common Scoter were sat offshore.

Tuesday 17th December 2024

 

Southbound 4 Wigeon, 2 Brent, 2 Great Crested Grebe, Pochard & Teal with northbound 5 Brent, 2 Common Scoter & Red-throated Diver. Otherwise predictable with 3 Turnstone & Rock Pipit at the point plus the now resident Cetti's.

Ringing: 1 House Sparrow.

Monday 16th December 2024

 

329 Cormorant went out fishing. Offshore movements minimal. Rock Pipit & Turnstone on the point. Stock Dove is worth a mention & 3 Cetti's advertised their presence in the milder conditions.

Sunday 15th December 2024

 

Fairly predictable. 518 Cormorant headed out to go fishing. Southbound 12 Brent, 4 Wigeon, 3 Great Crested Grebe, 2 Common Scoter & Red-throated Diver with northbound 3 Gannet, 2 Brent & Red-throat. 11 Kitts going south were presumably the same birds that pulled in behind the Stenna Britannica with other gulls going out. 7 Linnet were the first for a while. 2 Turnstone & the Rock Pipit were on the point. Very few Starlings around at the moment & no roost at the north end of the reserve like last winter.

Ringing: 1 Blackbird.