# Big River Watch vs Bat Detector

The clearest difference is review sentiment: Big River Watch at 100% against Bat Detector's 40%. Bat Detector's advantage is update cadence (monthly vs every 4 months). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Big River Watch ships an update every 4 months, Bat Detector monthly. The most recent releases landed on September 24, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Big River Watch | Bat Detector |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (4 ratings)](https://appshunter.io/ios/app/bat-detector/id6504186190/reviews)** |
| Number of ratings | — | **4** |
| Positive reviews | **100.0% of reviews** | 40.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Monthly** |
| Monetization | Free | Free |
| Size | 32 MB | 136 MB |
| Requires iOS | **14.0** | 15 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 9+ |
| Developer | [The Rivers Trust (UK)](https://appshunter.io/developer/1704314996) | [Phil Atkin](https://appshunter.io/developer/1751268739) |

## What reviewers say

### Big River Watch

[App page](https://appshunter.io/ios/app/big-river-watch/id6463412601)

Participate in citizen science by observing your local river and reporting on wildlife, water quality, and pollution. Your submissions contribute to a valuable dataset supporting river restoration efforts across the UK and Ireland. The app includes identification guides for wildlife and pollution.

**Highlights:** Citizen science river surveys, Record wildlife and pollution, Upload river photographs, Wildlife and pollution ID guides, Offline survey submission, Contribute to river restoration data

**Features:** macOS Compatibility

**In-app purchases:** none


### Bat Detector

[App page](https://appshunter.io/ios/app/bat-detector/id6504186190)

Listen to and record the ultrasonic sounds of bats using your iPhone or iPad. This app reveals bat acoustics through heterodyne detection and 16x time expansion, making their calls audible and musical. It also offers full-spectrum recordings triggered by bat sounds.

**Highlights:** Heterodyne bat detection without manual tuning, 16x time expansion for audible bat sounds, Full-spectrum recordings triggered by bat sounds, Real-time sound demodulation, Preserves harmonic relationships in bat calls, Supports European and global microbats

**In-app purchases:** none


## Frequently asked questions

### Is Big River Watch free?

Big River Watch is free to download, with no in-app purchases.

### Is Bat Detector free?

Bat Detector is free to download, with no in-app purchases.

### Do Big River Watch or Bat Detector have ads?

Neither Big River Watch nor Bat Detector shows ads.

### Which is updated more often, Big River Watch or Bat Detector?

Big River Watch ships an update every 4 months, and Bat Detector monthly. Most recently, Big River Watch was updated on September 24, 2026 and Bat Detector on October 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*